Q: Question re: "Start from your Mac OS X Install disc; use Disk Utility"

Question (?) Mark, Blinking Folder, or Gray Screen at Startup

These are related but not identical issues. Their causes are outlined in Intel-based Mac- Startup sequence and error codes, symbols. Solutions may be found in:

A flashing question mark appears when you start your Mac

A flashing question mark or globe appears when you start your Mac

Mac OS X- Gray screen appears during startup

In most cases the problems may be caused by one or more of these:

a. Problem with the computer's PRAM - See Resetting your Mac's PRAM and NVRAM.

b. Boot drive's directory has been corrupted - Repair with Disk Utility.

c. Critical system files are damaged or deleted - Reinstall OS X.

d. The disk drive is physically non-functional - Replace the hard drive.

Note that the information I have provided is what Apple recommends, If other users suggest different solutions than found here, then be sure what they recommend does not impact on your warranty, if any, or ability to get continuing Apple service.

Please don't start removing drives or changing cables unless you know what you are doing and have exhausted other non-invasive alternatives outlined here. If you perform any work yourself that is unapproved by Apple, then you will void any warranty you may have and lose all further Apple Support.

Repair the Hard Drive and Permissions

Boot from your Snow Leopard Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer.

If DU reports errors it cannot fix, then you will need Disk Warrior and/or Tech Tool Pro to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.

The main difference if you are using Lion or Mountain Lion is that you must first boot from the Recovery HD. Simply boot from the Recovery HD to perform the above.

Reinstall Snow Leopard Without Erasing The drive

1. Repair the Hard Drive and Permissions

Boot from your Snow Leopard Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer.

If DU reports errors it cannot fix, then you will need Disk Warrior and/or Tech Tool Pro to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.

2. Reinstall Snow Leopard

If the drive is OK then quit DU and return to the installer.  Proceed with reinstalling OS X.  Note that the Snow Leopard installer will not erase your drive or disturb your files.  After installing a fresh copy of OS X the installer will move your Home folder, third-party applications, support items, and network preferences into the newly installed system.

Download and install Mac OS X 10.6.8 Update Combo v1.1.

Reinstalling Lion/Mountain Lion Without Erasing The Drive

Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.

Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the main menu. Repair the Hard Drive and Permissions as follows.

When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the main menu.

Reinstall Lion/Mountain Lion: Select Reinstall Lion/Mountain Lion and click on the Continue button.

Note: You will need an active Internet connection. I suggest using Ethernet if possible because it is three times faster than wireless.

a blinking question mark on a folder.  This means your mac could not find a valid OS on your harddrive.  Either the OS became corrupted or your harddrive has failed ( among the most likely ).

See if your machine is semi present...

The startup manager will list all of your bootable partitions then give you a choice of which to boot.  Hold down the option key then power on. Continue holding down the option key until you see the startup manager. This brings up the startup manager. Click on your hd or disc. Click on right arrow key.

Did your machine come with a dvd?  Boot it and attempt to repair the hd.

Is either of the dvds black?  These are the universal install dvds.  I'd try a black dvd first.   You will have to try the others.  Sometimes the dvd disc gives hints to what machine it matches.

I suspect disk corruptions.

verify & repair your startup drive

To verify & repair you file system on the startup drive, you will need to run disk utility from you installation DVD.

This article  will tell you how to get to disk utility.  Once in a disk utility, you can go and attempt to recover the disk.

http://support.apple.com/kb/TS1417

To repair your startup drive, you will need to run disk utility from your startup DVD.
Mac OS X 10.4: About the utilities available on the Mac OS X 10.4 Install DVD

http://support.apple.com/kb/HT2055

How to run disk utility from your startup DVD.

1. Insert your  startup DVD  into your reader.  Power down your machine.  Hold down to the c key.  Power on your machine.  This will bootup your startup DVD.
2. This will bring you to a panel asking you for your language.  Pick your language.

1. You you come to the Install Mac OS panel.  Do not install.
2. Click on Utilities menu item.  This will give you a pulldown list of utilities.
3. Click on the disk utility.
   
4. You are now in disk utility.  Pick your disk.  Click on repair it should be on the lower right of the panel.
5. Once the repair completes successfully, you should update your permissions.

Robert

I'd suspect that the disk drive has gone bad.  You could buy an external disk drive.  You will have to check what ports are available.  I'd guess firewire 800. Firewire will be best.

I recommend you do a google search on any external harddrive you are looking at.

I bought a low cost external drive enclosure. When I started having trouble with it, I did a google search and found a lot of complaints about the drive enclosure. I ended up buying a new drive enclosure. On my second go around, I decided to buy a drive enclosure with a good history of working with Macs. The chip set seems to be the key ingredient. The Oxford line of chips seems to be good. I got the Oxford 911.

I'd give OWC a call. 1-815-338-8685.

FireWire 800 + USB 3, + eSATA

&

save a little money interface:

FireWire 400 + USB 2.0

This web page lists both external harddrive types. You may need to scroll to the right to see both.

http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/eSATA_FW800_FW400_USB

     (2) FireWire 800/400 Ports (Up to 100MB/s / 50MB/s)

     (1) USB 3.0 Port (Up to 500MB/s / 60MB/s)

     (1) eSATA Port (Up to 300MB/s)

Has a combo firewire 800/400 port.  Not sure what this is.  Looks like you will  need 400 cable.

http://eshop.macsales.com/shop/ministack