Hello and welcome to my User Tip
If this User Tip appears to be quite involved, it's designed to very through and systematic process to achieve success.
It's designed for those who already have a good familiarity with how Mac's work, is almost all Apple support documented.
If it's too much, there are local PC/Mac software repair and data recovery services, for hardware repairs you should take it to a Apple Authorized Repair. Read the disclaimers at the bottom here.
- Later steps usually depend upon earlier steps being performed. Only Step #17 and 20 are harmful (to your data) and marked.
- The process of elimination is designed to narrow down your problem and expose unknown ones, fix it yourself.
- If you have a wireless keyboard, you will need to use a wired/built-in one to perform the at boot commands.
- Disconnect all other hardware from the problem Mac. If you have a firmware password, that will have to be disabled first.
- Stable/fast Internet is required, preferably a Ethernet cable to your router, or if the modem, powered off/on to reset it.
If you hear these hardware issues:
- Grinding, clicking or other never before heard strange sounds coming from your hard drive, always requires Disk Utility > repair, SMART status bad, it's likely failing, especially if it's more than 5 years old or has been subjected to shock. Skip down and do #9 immediately, do #3 and take the machine in for service or replace hard drive yourself if possible. Another sign of a failing boot hard drive is seeing a lot of spinning beachball action, slow drive etc., (off the Internet/network to confirm)
- Beeping issues indicate bad or faulty RAM, or even a damaged logicboard. Return the factory RAM and/or #3 extended Hardware Test.
If you see this hardware issue:
- Distorted video, artifacts on the screen, zig zag lines (but not dots or "stuck pixels") it's likely a failing video card. "Stuck pixels" are a monitor issue as so are thin straight lines from top to bottom (the machine can continue to be used). Do #3 and #9, take the machine in for service.
What you will need if on 10.6:
- 10.6 Snow Leopard - clean scratchless boot disk required. Use a tiny bit of rubbing alcohol and a clean soft cloth to polish.
- 10.6 has 2 types of disks: 10.6.0-10.6.8 colored machine specific only, w/free iLife suite (can't be used with another model).
- 10.6.3 Retail Disk for installed at factory 10.4-10.6.2 Intel processor Mac's. Macs that came new with 10.6.3-10.6.8 can't use.
- Get the free MacTracker for details about your Mac, essential for picking the right 10.6 boot disk version/RAM amount.
- Need a 10.6 disk? Call Apple via phone (only) to order these disks. Machine specific has free iLife, not on 10.6.3 white disks.
What you will need if on 10.7-10.8:
- 10.7 Lion, 10.8 Mountain Lion requires AppleID and password if installed via AppStore and/or to restore iLife.
- 10.7-10.8 installed a "Recovery HD" partition on the boot drive that acts like a boot disk. Use no 10.4-10.6 boot disks.
- 10.7-10.8 recent Mac's have Internet Recovery, is downloaded from Apple's servers for whole drive repair/format
- 10.7-10.8 upgraded Mac's with no Internet Recovery can use This Method their own or matching OS X version machine.
Other things you will need:
- Another Firewire Mac + cable/adapter? Target Disk Mode For #9, #11 (and extreme methods #20, entire drive erasure.)
- You will also need time, tenacity, reasoning ability and lots of patience to learn, it's a lot to take in a short time.
- Personal data is unique can't be replaced, as OS X and programs can. Do #9 as soon as you can get into the machine.
- External storage drive to save recovered data for #9, in addition to your current backup system.
- After your machine is fixed, be sure to investigate any performance related issues here: Why is my computer slow?
Ok, here we go friends, roll up your sleeves. ________________________________________________________________________________ __________________________
Firmware "forgets" what volume to boot from:
- Flashing question mark/folder (can't boot into Windows /OS X) jump to #4 to see if it's a easy fix first, else #1-8+
- If your Mac boots to "Utilities" it's likey the firmware "forgot" what to boot from, try #4 or else return to #1-8+
OS X not booting issues:
- Gray, blue or white screen and/or loading bar - OS X isn't loading/corrupt/drive issue, run through the Steps below
- Bar goes across screen at update reboot - likely a firmware update install, not a issue. #3 & #5 to check drive optional.
- Boot up shows bar across screen, once or always - run through the Steps #1+ below
- "Your startup drive is getting full" - If Computer is booting > "Storage Drive" NOT booting? > External boot drive
- "You need to restart" - Kernel Panic - can be caused by OS X and/or third party software, run through the Steps below
- One program that is not saving your preferences or not opening do #12 and #13. If iPhoto: Rebuild iPhoto Database
- Web browser is slow, other computers are fast: do #12 and #13. Run through the Steps if that doesn't work.
- Computer and WiFi related issues: Could be two problems do the Steps and: WiFi, Internet problems, possible solutions
- Recently installed new RAM and Kernel Panic's?, and/or Beeping? > Bad RAM, #3 extended test overnight.
- "Permission Denied" with your own files, then skip and do #6, else run through the Steps below
- None of your problems fit the above? Skip and do #9 first if possible and disconnect, then Run through the Steps 1-16 below.
- Create a thread, tell people your hardware specs and operating system version and as much detail as possible, what you tried.
- Apple Menu > About this Mac > More information: Look for like "iMac 4,1" RAM amount and OS X version like "10.7.5"
- Your data recovery options: My computer is not working, is my personal data lost?
- Your secure data deletion options: How do I securely delete data from the machine?
Wired/Built in keyboard keys used here for the at boot commands
If the wired keyboard is one from a PC, the Windows logo key should be the same as the Apple/Command key
Start the Step by Step process of elimination procedure here
Your machine may or may not be booting properly at this point.
No harm will occur to your data with Steps #1-16.
No harm in resetting, may fix or flag another issue.
1. SMC reset (and other power/no power related issues)
Category: Hardware power related
Problems solved: Fans blowing with no activity, machine is not booting, power button pressed and nothing happens, problems with indicators, Magsafe has wrong lights, battery is not charging, monitor and graphics issues etc. If the battery is not charged (from like letting it sleep too long), let the Mac charge up awhile afterwards.
Other related hardware problems (optional):
Check battery status: Hold option/alt key down while clicking on the battery icon in the menu bar, top right corner.
Magsafe: Use the correct/matching power supply charger with your Mac, not a less powered one from another Mac.
2. PRAM reset
Category: Hardware related
Description: PRAM stores certain system and device settings in a location that Mac OS X can access quickly. Exactly which settings are stored in the computer's PRAM varies depending on the type of computer as well as the types of devices and drives connected to the computer.
Instructions: Apple: PRAM reset
Turn on the computer. Immediately press and hold the Command Option/Alt p r keys. You must press this key combination before the gray screen appears. Continue holding the keys down until the computer restarts, and you hear the startup sound for the second time. Release the keys.
Resetting PRAM may change some system settings and preferences. Use System Preferences to restore your settings in each user account.
>>Later make sure your date and time in System Preferences is correct or WiFi connection issues may occur
Change and then reset your monitor settings to remind the firmware you just purged of the correct settings if strange monitor issues occur.
Problems resolved: Depends upon hardware and connected devices.
3: Hardware Test
Category: Hardware only related
Description: Apple's Hardware Test, does a internal investigation for hardware related issues.
Instructions: Apple: Hardware Test
Need to have a Internet connection, hold the D key down for quite some time while booting the machine to load it from Apple's servers.
For beeping issues, that's usually a Random Access Memory issue, run the extended test overnight.
Return the stock RAM to the machine or if it re-occurs, contact the third party supplier for exchange. If Apple's RAM contact them.
Continue on, just because Hardware Test gives a error doesn't always mean the machine completely dysfunctional enough to get at your data.
4. Startup Manager
Category: Hardware related
Description: Startup Manager allows one to select other bootable items, disks, USB thumb drives, volumes etc.
Usefulness: For determining if a boot up volume is available or not.
Instructions: Hold option/alt key down at boot time, and select your OS X boot drive and click the arrow to boot it.
If your normal boot volume does not appear, it doesn't always mean the drive is dead or you lost your data.
Startup Manager only shows bootable volumes, obviously if your Mac is not booting there is something further wrong with the data on the boot volume. Proceed with the Steps.
Problems solved/possible solved:
Not booting into OS X/Windows from the other Hold option/alt key and set the startup disk in system preferences, also see #2.
Eject a stuck optical disk - Select the optical disk (if present) and press the eject key on the keyboard (press eject key regardless)
Flashing question mark issue while trying to boot - Means the firmware can't find a bootable drive or partition, could have forgotten or it might be a dead /failing drive/cable or Mac hardware issue.
Hold option/alt key at boot to see if it's there, boot and then set the Startup Disk in System Preferences to remind the firmware what drive to boot from, if this is not resolved, then start from Step #1 and work down.
5: Disk Utility
Category: Hardware related
Description: Apple's Disk Utility repair and formatting program
Problems solved: Repairs file structure of drive or partition selected.
10.6 users - clean and polish the bottom of the 10.6 disk (no other) with a soft clean cloth and a tiny bit of rubbing alcohol. Never touch or rest the bottom of the disk on any surface, if not possible choose a soft clean cloth or plastic jewel cd case.
• Insert the disk and Hold c or option/alt key down and tap the power button to boot from the 10.6 installer disk.
• Select Disk Utility from under the Installer Utilities menu.
• Select the drive or partition on the left, click First Aid > Repair Disk & Permissions.
10.7-10.8 users - hold command r boot from Recovery HD partition (only, use no 10.6 disks!!!), it's a bootable section on the boot drive itself that's like install cd.
• Select Disk Utility from the menu option.
• Select the drive or partition on the left, click First Aid > Repair Disk & Permissions.
Alternative full drive method for newer machines on Internet connections: Command Option/Alt r held at boot for Internet Recovery.
If you can't see your internal drive in Disk Utility, or if the Recovery HD doesn't boot, then it's likely a hardware problem, try a Internet Recovery if you machine has it or Firewire Target Disk Mode if you have another capable Mac + cable.
See for accessing and/or data recovery: Is my personal data lost?
Other related problems:
Force eject a stuck disk - hold the trackpad or left wired mouse button down while booting, the hardware should force eject the disk, or use #3 Startup Manager (hold option/alt key at boot) and select the disk and/or then use the eject key on the keyboard, even if no disk appears in Startup Manager the stuck disk can be ejected by pressing the eject key.
If Disk Utility repairs the drive: run repair again to make sure.
If DU gives a error and can't repair the drive: you have a more serious drive issue, backup data off the machine as soon as possible. See #7 + #9, or #19. If you have a backup of your data off the machine, then do #20 Erase and Install OS X onto the Macintosh HD and start over.
If you see a "You need to restart your computer...": While attempting to boot off the installer disk (may be bad or the wrong one, replace) or from Recovery, you likely have a hardware issue, see #6.
Permissions keep "repairing" it's ok. See Disk Utility messages you can safely ignore
6: Reset User's Permissions (or password)
Category: User account related
Description: This repairs the user file permissions on the User account selected as Disk Utility doesn't repair user permissions, this is usually for "in a user account" type issues, can't log in, forgotten password. OS X is based upon Unix, which uses permissions setting on each and every file on the machine to control access.
Usefulness: Since you already have the 10.6 disk or Recovery HD partition booted up, might as well fix this as a possible in the search to resolve your issue.
On 10.6, hold c or option/alt key boot off the 10.6 disk and use the Password Reset under the Utilities menu
For 10.7-10.8 follow these steps:
Hold down the Command r keys while booting.
Select Terminal in the Utilities, Type resetpassword and hit Return.
Don't change the password if your just repairing user permissions, instead select the drive at top and the account your having issues with.
See an area labeled Reset Home Directory Permissions and ACLs. Click the button.
If you reset the password, it's a good idea to write it down, as sometimes it takes using it quite a bit before you fully remember it
If you have reset the password, you will likely have problems with Keychain see:
Problem(s) solved: Always having to enter admin password to delete user created/account files. Possibly solves can't log in issue.
Other related problem:
If you can't log into your sole account on the machine see #18 to create a new Admin account on the machine (advanced)
7. Safe Mode
Category: Hardware/Software related
Instructions: Reboot the computer holding the Shift key down. A progress bar goes across the screen.
Description: Performs various repairs and enters a more stable OS X environment free of third party at boot kernel extension and other files, disabling of certain hardware features, network etc. First thing to try when OS X refuses to boot.
Reboot again normally (no Shift key) to get out of Safe Mode.
More here, including invoking Safe Mode at Single User Mode (advanced): Apple: Safe Mode
If the progress bar stops, hangs or the machine doesn't boot for quite some time, then you have a further problem. Do #4, consider other steps.
If you have always see a progress bar upon boot, even if the shift key is not pressed, then you have a further problem. Do #4, consider other steps.
If you can only get into the machine while the Shift key is pressed Do #4 and do #8 others steps depending.
"You need to free up space on the startup disk"
If you saw this message or perhaps you know you just copied a huge amount of data to the boot drive and now it's not booting up.
Hold the shift key upon boot to get in and delete/move some unnecessary large items to another drive, usually some movies will do it. Moving requires copying to the destination and then deleting the original. Reboot a couple of times normally to see if you can get in again.
Look at your Utilities > Activity Monitor > Drive usage to make sure it's below 80% filled, move any items to a external storage drive from inside your users folders of Movies, Documents etc etc. Applications usually can't be run from a external source and are too small to bother.
TimeMachine is a rotational backup, not permanent. Look at "Storage Drive" here for more space: Most commonly used backup methods
If holding Shift key doesn't work to get you into the machine this will work to remove files: Create a data recovery, undelete boot drive
Problems possibly bypassed:
Computer freezes when booting on gray screen, white or blue screen at boot time (see #8), allows one to get into the machine to perform backup #9 in case a #20 Erase and Install OS X is later required.
Also to check on third party software for updates or uninstall that has a at boot kernel extension file loaded at boot time and causing the freeze up. See #11-15 for possible solutions.
8: Reinstall Just OS X
Internet: may be required (10.7-10.8 yes)
Category: OS X and bundled Apple software related
Description: Replaces only OS X and bundled Apple software programs with a new copy. Small portions of third party software installed in OS X itself is removed in the process, but they can be reinstalled later. Programs in Applications folder or the User account folders are not touched.
This will usually work to get you a booting machine again. Which one then addresses any third party software issues.
Problems solved or possibly solved:
"Gray Screen with spinning gear at boot" type issues... https://support.apple.com/kb/TS2570
"Blue or White screen at boot" type issues same as gray screen... https://support.apple.com/kb/TS2570
Some "You need to restart" kernel panic type issues if it's OS X causing it: https://support.apple.com/kb/TS3742
"Safe mode freezes on progress bar" type issues https://support.apple.com/kb/TS3148
Solved: OS X and/or bundled program(s) related issues not resolved by other means.
Solved: Outdated or unknown/older conflicting at boot third party kernel extension files.
10.6 users - clean and polish the bottom of the 10.6 disk (no other) with a soft clean cloth and a tiny bit of rubbing alcohol.
• Insert the disk and Hold c or option/alt key down and then boot the computer from the 10.6 installer disk.
• Second screen, select your boot drive and simply install OS X again.
• When you get into the machine, immediately Software Update (#10), reboot and repeat until clear. Important!
Force eject a stuck disk - hold the trackpad or left wired mouse button down while booting, the hardware should force eject the disk, or use Startup Manager #3 and select the disk and then use the eject key on the keyboard.
10.7-10.8 users - hold command r or option/alt key and boot from Recovery HD partition (only, use no disks)
• It's a bootable section on the boot drive itself that's like install cd. See this: https://support.apple.com/kb/HT4718
• Some newer Mac's also have Internet Recovery, hold command option/alt and r keys near a fat reliable Internet connection
• Have a good reliable fast Internet connection (+5 Mb/s) and install OS X 10.7-10.8 from Apple's servers, you'll need your AppleID and password.
All 10.6-10.8 users
When you get into the machine, Apple Menu > Software Update (#10) repeatly until there are no additional updates.
Reinstall any third party software that fails to work from original sources, but first verify the developer has a update that is compatible with the OS X version your using. (see Apple Menu > About this Mac for the OS X version)
None of the above Steps fixed your non-boot issue....
If you need to get your data off.
Another Firewire Mac + cable/adapter? Target Disk Mode For #9, #11 (and extreme methods #20, entire drive erasure.)
Find the closest Apple repair or distributor: https://support.apple.com/kb/HT1434
If after a hardware evaluation by Apple clears any hardware issues, consider doing #20 after successful data recovery efforts concluded.
...Or at this point your machine should be booting normally
9. Backup personal data off the machine
Category: User account related
Description: Makes a easily accessible backup copy of just a users data in case in case of various corruptions to be used in a #20 Erase and Fresh Install" in case it might come to that or files to be used with a PC, older Mac, Linux machine, etc.
Users data is unique and can't be replaced like hardware, programs or OS X can be, you need to get at least two copies off the machine as soon as possible.
Don't count on just a single TimeMachine or clone backup, it might be corrupted.
Get a external storage drive from the local computer or office store and connect it to the Mac. USB is fine, don't go to large, match your internal drive size.
Ignore the TimeMachine backup if it asks, now is not the time to do that when your boot drive is having trouble, later yes.
The drive should be formatted already, but if not OS X will ask to format it or use Disk Utility:. Choose Partition: Option: MBR and Format exFAT for best compatibility, saving of large files for working with Mac's and PC's.
Warning: Formatting a drive or partition with existing data on it will erase that data!
Use the Finder > Go menu > Computer. Select your boot drive to open it, (drag and drop) copy the Users folders to the regular external storage drive with enough room, unmount the drive by dragging it to the Trash can, physically disconnect external drive when finished.
If you have a clone or TimeMachine, do this in addition to those so you have two backups of your data off the machine.
Maintain at least two backups of your personal data, easily accessible as possible, on separate hardware and separate locations at ALL times.
See "Emergency Quick Copy Method" here to a Storage Drive: Most commonly used backup methods
10. Software Update
Internet: required for download
Category: OS X related and bundled Apple software related
Description: Updates OS X to the current version, solves problems and updates Apple related software
Problems resolved: Varied, Apple bundled software updated to recent versions after a #8.
Instructions: Apple Menu >select "Software Update" enter password of a Administer of the computer. Repeat this procedure until Software Update has nothing to update any further. Important for 10.6 and prior OS X version users to repeat this function until clear.
If your Wireless is not working, you may be able to hook up a Ethernet cable to the router or modem (reset the modem power to get a new IP connection from your ISP). WiFi, Internet problems, possible solutions
Now leaves third party application(s) or a User account issue(s)
11: Disk Utility > Repair/Permissions (from the Utility folder)
Category: OS X related
Description: Repairs permissions in OS X (but not User account file permissions, see #5), does a more recent version than #4 Repair Permissions.
OS X is based upon Unix, which uses permissions setting on each and every file on the machine to control access.
Problems possibly resolved: Varied https://support.apple.com/kb/HT1782
Launch Disk Utility from the Applications > Utilities folder. Select your drive or partition on the left, click First Aid, then click Repair Permissions.
Permissions keep "repairing" it's ok. See Disk Utility messages you can safely ignore
Check the S.M.A.R.T. status of the drive, if failing you need to perform #9 right away and have the drive replaced.
You can choose to Verify Disk for errors, but if it gives any error or "drive can't be unmounted" etc you need to proceed to Step #4 as that is the method to Repair the drive and is advised.
Note: If Disk Utility says it can't "unmount" the drive, that's because another program is using the drive (likely Spotlight) and thus erasing is not necessary, disable Spotlight or other programs accessing the drive (TimeMachine?)
12: OnyX cache cleaning
Internet: required for download
Category: OS X, application and User account software related
Description: Gives OS X, application and user account caches a enema, lets then rebuild again new, resolves strange and unknown issues based on cache files being corrupted .
Only cache files are removed, not users data, files, programs or OS X. Some settings will be set back to normal in Finder and other locations. Spotlight will rebuild a new database.
Problems possibly resolved: Varied: Flash install issues, Dock/Finder/File issues, "ghost files", performance and privacy related
Apple doesn't supply a easy method for the user to self clean the caches, thus we have to turn to third party software.
Use the free OnyX matching your OS X version and run all the initial checks, stop if any give a warning, you have a bigger problem. See #4
Run though all the Maintenance and Cleaning aspects (except don't delete the log files) and reboot at the end (must)
You must be through running all the maintenance and cleaning aspects as this is a "catch all" method and any number of corrupted caches may be responsible for your issues. You need to REBOOT at the end of using OnyX. Canceling the in-between reboot requests is fine.
Read Step #13 and perform the Verify > Preferences before rebooting at the end of using OnyX.
10.8 users: May need to System Preferences > Security > Gatekeeper to "Anywhere" to accept software from the web.
Just a few of OnyX many successes: and and and
13: Corrupt preferences files
Category: Application and User account related
Description: Preference files are basically that, they store your user preferences for that particular program inside the Users/Library folder (now hidden your protection in 10.7+) they can become corrupt which won't save your preferences settings or fail to launch the associated program responsible.
Problems possibly resolved: Varied, depends upon the program involved. Cures desktop picture that won't change issues for one.
Preference or .plist file checker in OnyX > Verify (#12) show the corrupt ones and write them down.
Or if the program responsible or system preference doesn't launches and/or doesn't work, or doesn't save the changes you made in it's preferences:
It's corresponding .plist file is likely corrupted. It's a easy fix, find and delete the responsible preference (plist file), reboot and launch the program, it recreates it's own again automatically and you have to reset your preferences again for it.
Use the Finder: Go menu > Go to Folder and paste: ~/Library/Preferences and then press Go!
com.apple.systempreferences.plist (corrupted/not launching System Preferences)
com.apple.desktop.plist (corrupted/not working desktop picture changes)
com.apple.safari.plist (safari issues)
com.yellowmug.SizzlingKeys4iTunes.plist (random third party sample plist.)
Trash the corresponding .plist file manually, reboot and relaunch the problem program again and reset preferences.
10.7+ the Users/Library folder is hidden, use the above method to open that folder. Also there may be two copies of the same .plist file, one is the original lock file and can not/should not be deleted. Delete the other that you can easily drag out to the Trash.
See this for more detail: Deleting the System Preference or other .plist file
14: Third party and Apple software
Internet: may be required
Category: Application related
Description: Locate the problematic program responsible in a process of elimination
Uninstall or Reinstall (using the developers installer/uninstaller) all third party software, install one at a time and test to find the culprit.
If a program itself is corrupted, it usually has problems in other logged in accounts. Reinstalling it will overwrite it with a fresh copy.
Include any third party system preference panes (right click on them to remove), software to run keyboards or other devices, plug-ins, menu items etc. or check for updates.
If you poked around in your Console log files (#15) you should have seen programs that are having issues or reporting kernel panics.
Apple iLife and some bundled software can be reinstalled from the 10.6 disk by running the bundled installer, then Software Updating until clear.
Some Apple bundled software like PhotoBooth is only installed via the #8 Reinstall Just OS X method.
If you've upgraded from 10.5 to 10.6 via the 10.6.3 disk, you can extract 10.5 programs from the disk using Pacifist from CharlesSoft.
Some Apple bundled software can reinstalled via the #8 Reinstall Just OS X method above.
If you have upgraded from 10.6, and still have the colored machine specific disks, iLife can be reinstalled by running the bundled installer.
For restoring iLife from the AppStore, read this: https://support.apple.com/kb/HT4718
Programs can be redownloaded from AppStore by holding option key and clicking on Purchases.
Third party browser problems: uninstall add-ons, uninstall and reinstall browser,
Plug-in check for all browsers
Uninstall Silverlight: https://www.microsoft.com/getsilverlight/get-started/install/removing-silverligh t-mac.aspx
Reinstall Flash: http://get.adobe.com/flashplayer/
Further Flash assistance: How to install Flash, fix problems
Reinstall Silverlight: https://www.microsoft.com/getsilverlight/Get-Started/Install/Default.aspx
Apple bundled programs (including Safari) can be reinstalled along with a #8 Reinstall Just OS X method.
Older versions of Safari can be downloaded from Apple's Download page, however it's not advised to use them, switch to Firefox or Chrome instead if you have older OSX version running.
iTunes can be reinstalled from Apple's web site: https://www.apple.com/itunes/
iPhoto rebuild database: https://support.apple.com/kb/HT2638
Sometimes it's a file problem that is automatically loaded when the program launches, like iPhoto for instance, you'll have to do a tedious process of elimination to find the culprit, like a corrupt picture in a huge iPhoto Library folder.
One can right click on the iPhoto Library and "show package contents" to access the Originals folder containing one's original photos.
Uninstall Perian: It's no longer being supported, so uninstall it.
Open the System Preferences. Select the Perian pane and 'Remove.' Now 'Show All' preference panes, control-click the Perian pane and 'Remove "Perian" Preference Pane.' Use the free Mac version of the Video Lan > VLC Player to play non-Quicktime compatible media content.
Uninstall Mackeeper: Search the forms and reviews all over the Internet, it's not very well liked, problematic.
Uninstall always on, loads at boot time and/or restrictive anti-virus/anti-malare software:
Especially very restrictive anti-malware like Norton which tends to lock down your machine.
For recent Mac's it's really not needed as malware for OS X is extremely low, just bugs up the machine and makes it slow or problematic. Apple tends to respond fast to fix issues and also does sudden, under the hood changes which tends to break this type of software. Also if one anti-virus maker finds malware doesn't automatically they cooperate 100% with others, as anti-malware vendors are in competition with each other.
For the low amount of Mac malware out there (almost zero) your likely best not running always on anti-malware. Rather install the free, run as you need it, ClamXav for cleaning the Windows files of their malware, complying with corporate requirements and for the extremely rare Mac file trojan.
If your on a OS X version Apple no longer supports, (like 10.4 and 10.5 and soon 10.6) then you need to read this: Harden your Mac against malware attacks
For more in depth performance issues see this: Why is my computer slow?
15: Check your Console Logs and Activity Monitor
Category: Application and OS X related
Description: Locate the problematic program or process responsible in a process of elimination
Activity Monitor is in your Utilities folder, look for runaway processes (select "All processes") notice anything odd? taking 100%+ CPU and your not doing anything?
Force Quit the runaway process. Reboot and see if that clears the issue. If not then investigate or ask questions.
You can use this site to investigate your processes and what belongs to what to try to find what is causing your problem
Always on anti-virus, MacKeeper (junk) may be consuming a lot of the computers resources behind the scenes, uninstall them.
Check your boot drive is not past 80% filled (Applications/Utilities/Activity Monitor.
If your drive is full then see Storage Drive: Most commonly used backup methods
Console program > System Diagnostic log file look for a section like the below
Example only: yours may be different, or may not contain any third party at boot kext files :
com.apple.filesystems.cddafs 2.4.3 - last loaded 33453549226
Notice the first loaded kext (kernel extension) files (in bold) are not from Apple?
If your machine only boots into Safe Mode (Shift key) these may be the cause.
At boot kernel extension files are third party software that loads when the computer boots up, if there is a problem with these you get the famous "Gray screen, Apple logo and spinning thing" perhaps even a white or blue screen. Holding the Shift key down while booting prevents these from loading and lets you get into the machine to repair the third party software responsible.
Kernel panics are those black screens with the "You need to restart" and are usually caused by buggy or outdated third party software, regardless if they have a at boot extension or not kext files can get loaded later when the program runs, like in startup or log in items, or 10.7+ auto launching of programs.
However OS X itself or bundled Apple software could be the problem too and a #8 Reinstall Just OS X solves those issues in one shot, but also removes these third party at boot kernel extension files.
Looking over the other Console logs is important for detecting what third party software(s) is possibly causing the problems. See #15.
One can open the System/Library/Extensions folder and drag out any of these non-working third party (only) kext files out and reboot as a last resort. This is for cases where one doesn't have a means right now to reinstall/update the software or have a 10.6 install disk on hand or a reliable Internet connection to download a fresh copy of 10.7/10.8 from Apple's servers.
I advise using the developers uninstaller as there may be other parts located elsewhere and you might get strange behavior etc.
Be careful not to select a Apple or OS X needed kext or one your not sure is from the third party software else your machine will fail to boot.
Look at this User Tip: Why is my computer slow?
16: Create a new User Account
Category: User account related
Description: This method is very useful for determining if the problem is in located within the one User account or not, usually something not covered in the above steps or deep inside the Users/Library folder for instance (hidden in 10.7-10.8), which store files that programs use for that certain user account only.
If you have a problem with a program that only occurs in one user account on the machine, then this method will establish a new user account which you can then test that theory and decide if you can find/replace the problem account program specific file causing your issues, or wind up having to do a #17.
Create a new Admin account in your System Preferences then log into this new user.
Test programs to rule out a Apple bundled program issue or OS X issue, you'll see right away if your problems discontinue.
Programs store it's User specific attributes in the User account (User/Library, now hidden in 10.7+) and these can become corrupted.
Uninstalling and reinstalling the program responsible may not work, the files remain in the (hidden) User/Library folder.
#17: Delete and Recreate the Problematic User Account will restore a new blank User/Library
In 10.7-10.8 the Users/Library folder is hidden, but can be accessed by entering ~/Library in the Finder > Go menu > Go to Folder selection.
A good free program called Easy Find will allow one to search hidden files on their machine to locate the problem one. Usually programs will label their support files with a company or product name, so searching for all instances of "Flash" will give you a clue where to search in your User Account for these possibly corrupted files. 10.8 users may need to temporarily turn off Gatekeeper in System Preferences to download software from outside sources.
If you've eliminated all third party software as a problem, and created another user account and the problem continues there, or you can't boot normally (no shift key), then you need to do #8 Reinstall Just OS X method to rule out OS X and bundled Apple programs as a culprit.
Continue to the next step #17 if your sure it's a problem within that one original User account.
Halt, who goes there?
If you were following along and doing these Steps to try to resolve your issue, you should probably then check back in your thread and report the results and/or ask the opinions of others on the forums before proceeding. Provide as much information and detail as possible so we can form a image and look your machine specifications up on our databases.
Data destruction will occur here on out, the steps may be too hard and/or might be overkill for your problem.
Proceed if your sure and have exhausted your Data Recovery Efforts, ready to risk losing your file as it's going to happen.
17: Delete and Recreate the Problematic User Account (hard)
Warning: Deleting the problematic user account will destroy any data in that user account.
If you don't have a recent copy of the user files off the machine, you need to consider the Data Recovery Step here (if the machine won't boot) or if you can't log in (see #18) first before proceeding with deleting the problematic account. Once the files are off then your safe to proceed.
If you want to save web browser bookmarks, you should try to export those first while in that problematic user account if possible.
Programs that are stored in the global folder called Applications is accessible by any user, you don't need to bother backing these up when deleting the account.
If your problem is localized to the one user account, likely in the Users/Library folder (which is now hidden in 10.7+), you can try restoring this folder (or the entire User folder) from earlier TimeMachine or backup. If the entire User folder is restored, make sure you saved the more recent copy of the User folder to a external storage drive (step #9) so you can return recent files.
Create another Admin account in System Preferences, copy files out of the problem user, delete the old account, reboot and re-create the old named account and return files, thus recreating the User/Library folder devoid of corruption and settings.
Sometimes the problematic user account can't be logged into, thus use the second Admin account (#18) to access the other and transfer files out.
If you have only one Admin account on the machine and can't log into it, there are ways to create another Admin account via Single User Mode (root, dangerous) via the command line. It's a advanced step, see #18.
What is your personal data and where is it stored?
The contents of your User(s): Music, Pictures, Documents, Movies, Desktop etc., aka visible "Home" folders.
The "User"/Library folder (hidden in 10.7+) contains certain settings, caches, specific program file and preferences tailored for that user account.
I would copy the "User"/Library too, rename it so it won't conflict, but don't use it to restore back until you have detailed information what it contains and if you can restore it or parts of it back or not. It changes by Apple OS X changes and by third party software makers, may be the source of your corruption/problems. So a new User/Library is best when you recreate the problem account anew.
Transfer files between user accounts on the same machine?
Finder > Go menu > Computer
A window appears with your boot drive, double click on it to open
Inside is Users folder, double click to open it
Inside is your User accounts, double click on the one you want to send files too
Double click on the Public folder drop the files into the DropBox folder,
The permissions will change and can be used in the other user account when you log into it.
18: How to create a new administrator account on the machine (advanced)
Note: If your here for #18 Reinstall Just OS X, it's been moved up to #8
It's recommended to have at least one other Administrative level account on the machine at all times in case of problems with the sole Admin account on the machine which most users have by default on Mac's.
If you can't log in, or launch your user account, despite using Step #5 and resetting your password and have completed Step #8, this step will create a brand new Admin account which you can log into and perform necessary Software Updates or file extraction out of the other users account's.
10.6 Hold Command and s keys down while booting to enter Single User Mode (aka: "root")
10.7 Hold command and r keys down and boot into Recovery, open Terminal
Type each and press enter after each command.
The first line must be exact as "rm" is very dangerous if entered incorrectly.
Open System Preferences > Users and Groups, Click on the lock icon, enter admin password.
Select your old user account and click on the reset password button on the right
Enter the new password, write both passwords down less you forget. Reboot and log in.
19: Data Recovery efforts (advanced)
Used if you don't have a recent copy of your files off the drive, like it's not booting, or it's been reformatted, or files accidentally deleted, file structure of the drive is not functioning etc.
Don't despair, as long as the storage drive is functioning mechanically, even if the Mac is not or you can't boot into OS X, you can still recover data off the drive, even if it was deleted (but not overwritten) as long as it's not encrypted.
See this for a full evaluation of your data recovery options
Also if this is too much for you, STOP using the computer to prevent potential overwriting and take it to a local PC/Mac repair, which one of their main businesses is data recovery.
Apple's procedure it seems is to send you home with a external hard drive and "hope" TimeMachine will work, then erase your only copy of data when they fix the machine.
Local data recovery folks will image your drive passively with special software that does take hours to complete, but it's highly effective in it's recovery efforts.
Apple likely won't take that sort of time. If your data is valuable and worth more that $300, then take it to the local data recovery specialists.
20: Erase and Fresh install OS X (advanced)
(Internet required, 10.7-10.8 yes)
Permanent data destruction on the entire drive (all partitions) or just the partition selected.
No recovery possible. All programs, user files and operating system and even BootCamp may be gone forever.
You shouldn't be here if you still have user files you want off the boot drive: My computer is dead, is my personal data lost?
This is a very hard step for most, may want to experiment first: Create a data recovery/undelete external boot drive
The methods for a Erase are...
...you first launch Disk Utility (See #5...)
In 10.6 if the entire drive is selected to erase, Bootcamp will disappear. So select just the Macintosh HD partition if you want to keep BootCamp, however it's advised to try to do the entire drive and rebuild the GUID partition table which might be causing your issues.
On 10.7-10.8 your only erasing the Macintosh HD partition from the booted Recovery Partition, so you can only select the Macintosh HD or BootCamp partition to erase.
...and if on 10.6 select the entire drive makers name and disk size on the left to erase the entire drive of all partitions including Bootcamp....
...or if on 10.6, 10.7, or 10.8 just select the Macintosh HD partition on the left (contains OS X, programs and your soon to be erased files, but not BootCamp)...
On 10.6: Erase > Security Option > Zero All Data, then click Erase (or just Erase if you have a SSD)
On 10.7-10.8: Zero Erase is one selection from the right (middle selection), then click Erase, (or just Erase if you have a SSD)
If you have 10.6, don't have BootCamp or another partition, or don't care about it, or have a serious drive issue, the you should select the entire drive to erase.
In 10.7-10.8, since the entire drive can't be erased while booted from it, it's better to reinstall OS X first the use BootCamp software to remove the BootCamp partition as it will adjust the new space back into Macintosh HD partition automatically.
It's going to take some time, when finished, one quits Disk Utility and installs OS X like in #8 + Software Update and then go about installing programs and returning files from backup into the same named accounts, or restoring from a problem free clone or TimeMachine drive.
If your TimeMachine or clone drive is corrupted by the problems originally on the boot drive, then your just going to copy that corruption data back on.
Consider a fresh install of everything from original sources, then later you can vet the files and return them instead. Corrupted user files rarely take down the entire machine and easy to identify and eliminate. Return files last and from the Storage Drive (#9) into their same named account "home" folders of Music, Pictures, Movies, etc. as before, use #6 and repair User Permissions afterwards.
• 10.7-10.8 Installing and restoring iLife on machines that came with 10.7 or 10.8 (doesn't apply to machines upgraded from 10.6)
• Erase and installing 10.6 from the boot disks https://support.apple.com/kb/HT3910
Full drive erasure for 10.7 and 10.8 machines (advanced)
In the above method, one is command r booting into the Recovery HD partition, then erasing the Macintosh HD partition then installing OS X into it.
Newer Mac's can use Command Option r and boot into Internet Recovery (downloaded from Apple's servers) and perform entire drive erases, including EFI, Recovery HD and the GUID partition table.
Some Mac's that were upgraded to 10.7 or 10.8 are not capable of Internet Recovery, so they need to have a copy of Recovery HD on a USB thumb drive to catch the entire drive of everything.
If you can boot into only Recovery HD, then your should create this: Create a data recovery, undelete boot drive
OS X 10.7-10.8 on a external drive can be hold the option key bootable in Startup Manager, thus allowing full erase to the internal drive.
If you need more security in data deletion, I read this: How do I securely delete data from the machine
Disclaimer: I take no responsibility for any action you or others take upon machines and data using these instructions.
If your not sure, take your problem to local or professional software and data recovery specialists.
Provided as informational purposes only, no guaranty the information is accurate or will be updated to reflect changes.