Hello and welcome to my User Tip
This tip is designed to act as a methodical step by step guide to resolving unknown issues for 10.6-10.7 users.
None of the steps will hurt your machine or have a effect on the other steps, if followed as intended and it increases in complexity the further it progresses.
STOP if you feel anything is overwhelming you and seek professional assistance.
STOP and report back to your original thread any kind of warning or irregular behavior any of these steps give.
STOP if the procedure has resolved your issue obviously...duh.
I will give adequate notice if any of the steps may possibly or will delete your data.
If your machine is not booting, or
Gray, white or blue screen, spinning thing,
or "you need to restart" issues,
follow this guide instead, return to this one.
Please report back what steps you have completed to your original thread so we can assist further.
Also any machine specs, your OS X version, software installed, etc etc so we can visualize your machine as we can't see it.
1. Drag and Drop to copy
your Users file folders off the machine to a external storage drive (no TimeMachine setups now) and disconnect all drives.
If you have a TimeMachine drive or clone backup, do this step regardless because either or both of those could be corrupted.
If you can't do this now, the first opportunity you do, do this step, saving your Users data is priority #1 a all times.
If you don't know what a storage drive is or don't have a backup, then read this thread about backups.
2. Software Update fully under the Apple Menu, disconnect from the Internet.
Test. Is your problem a network issue or not? If not then go to 3
If so, then check for network related issues, reset your router etc.
Network issues are not resolved in this User Tip, I have some possible fixes here
3. SMC Reset https://support.apple.com/kb/HT3964
5. Hold Shift key boot (Safe Mode) and restart normally again https://support.apple.com/kb/HT1455
You will see a progress bar go across the screen, if it completes your good and you reboot and everything is fine, then good. Stop.
If your machine only operates in Safe Mode, or always see the progress bar upon booting then report that in your original thread. Go on to 6
Possible Solutions if further steps don't resolve it:
Could be a third party kernel extension problem as these are disabled in Safe mode. See Mac won't boot or "You need to restart"
Could be a drive or bad sector issue that the data can't be read by the computer.
6: Disk Utility > Repair Permissions from the Utility folder
Select your drive on the left, click First Aid, then click Repair Permissions.
You can choose to Repair Disk, but if it gives any error or "drive can't be unmounted" etc you need to proceed to next step. #7 as that is more reliable method to Repair the drive.
If you see it giving the same list of permissions fixed, "Warning SUID file changed and won't be repaired" type messages can be safely ignored.
7: Disk Utility > Repair Disk
(hold c and boot from the 10.6 installer disk) or (hold command r boot) from Lion Recovery HD, also Repair Permissions there.
8: Hardware Test https://support.apple.com/kb/ht1509
If it gives anything, write it down and consider taking it in for service. Stop. We can't fix hardware issues.
Find the closest Apple repair or distributor
A drive or RAM can be replaced by the user in some Mac's.
9: Reset User's Permissions
On 10.6, hold c or option key boot off the 10.6 disk and use the Password Reset under the Utilities menu.
For 10.7 Lion follow these steps:
Hold down the Command and R keys while booting.
Select Terminal in the Utilities, Type resetpassword and hit Return.
Don't reset if your Repairing Users Permissions, instead click on icon for your Mac’s hard drive at the top. Select the user account where you're having issues.
You'll see an area labeled Reset Home Directory Permissions and ACLs. Click the button.
10: OnyX cache cleaning and Verify > plist
This routine cleans all possible corrupt caches, doesn't delete your data or programs.
If any of the initial checks OnyX does gives a warning, then Stop and report, you have a serious drive or other issue.
Sometimes a corrupted cache file can cause strange behavior, slow machine, Dock doesn't work, beachballs effect, just general strangeness.
Use the free OnyX matching your OS X version and run all the initial checks
Run all the maintenance and cleaning aspects (except don't delete the log files) and reboot at the end (must)
This will give OS X a enema of sorts (won't delete file or programs) and let it rebuild all the cache and other files, including Spotlight.
OnyX also has a Verify > Preferences
(plist) file checker, show the corrupt ones and write them down. So while your in OnyX cleaning your caches, check for corrupted plist files too.
Use the free EasyFind to search for these corrupt .plist files and delete, reboot the machine and launch the program responsible and reset your preferences. Note: Spotlight doesn't "find" everything.
Usually one can find out if they are having a problem with a certain program or system preference not saving their screensaver etc which .plist is responsible.
They are usually located in the: use Finder > Go > Go to folder /Library/Preferences and press Go! Trash the corresponding .plist file manually, reboot and relaunch the problem program again and reset preferences.
com.apple.systempreferences.plist < for problems in system preferences
com.apple.safari.plist < for problems in safari
com.yellowmug.SizzlingKeys4iTunes.plist < for problems in SizzlingKey program
You don't have to perform routine maintenance on a Mac, it does it all by itself, consider this OnyX routine a "nuke the caches" and find the bad plist file sort of troubleshooting and repair step in resolving your issue.
10: Check your Console Logs
...for anything "kernel protection failure" or alerts to what is causing your problems. It's located in your Utilities folder or use Spotlight (hold command space bar) to search for it and open it. Some of these log files can only be seen in a Admin account.
11: Check all your installed third party software
Including any third party system preference panes, menu items etc for updates. Uninstall or Reinstall all third party software again.
12: Create a new User Account
Create a new Admin account in your System Preferences. Log into that new user and test, same problems? Used the same files? Not a file issue? Is it a particular program now working fine in this user? Uninstall and reinstall the program in the other User account to recreate it's support files in the User/Library (purposely hidden in 10.7)
Not So Easy
13: Delete and Recreate the Problematic User Account
Warning: Deleting the problematic user account will destroy any data in that user account. If you don't have a copy of the files, you may wish to consider the Data Recovery Step #15 before proceeding.
If your problem doesn't exist in the second User account and you can't resolve it manually in the problematic account, the issue is localized the first User account, likely a bad file or Library.
If you want to save web browser bookmarks, you should try to export those first while in that problematic user account if possible.
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 from TimeMachine or backup.
Create another Admin account, 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 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, so ask on the forums or in your thread as to receive guidance in it's procedure for your OS X version.
14. Reinstall Just OS X
Doesn't touch users or most programs, will kick out anything "non-Apple" out of OS X
Warning: Possible user data destruction with this method, consider step #15 before proceeding.
No user data destruction in most cases as only OS X and bundled Apple programs are replaced.
You need to Software Update fully right away after this procedure is undertaken to get OS X and bundled programs up to date with your files.
You should consider data recovery efforts below or use a local PC/Mac data recovery service (any good shop will do) if you don't have any backups of your data off the target drive. Proceed at your own risk.
15: Data Recovery efforts
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.
15: Zero Erase and Fresh install OS X
Warning: permanent data destruction on the entire drive or partition selected. No recovery possible.
Wipes everything method. Everything erased, the drive bad sectors mapped off, everything new except files from storage drive, no clone or TM restores.
For secure deletion for the paranoid read this:
16: Replace the hard drive
if allowed for your machine, reinstall the OS and everything.
Only should do if you're out of AppleCare/ warranty or for security reasons as Apple needs the filevault password to fix the machine.