Disk Utility tells me to repair disk permissions from the DVD, but my DVD drive isn't working

Question

I have an iMac with Snow Leopard that shows it is low on disk space. In Disk Utility, I select the hard disk and click "Verify Disk". It gives me an error and says to click "Repair Disk Permissions".

When I click "Repair Disk Permissions", it tells me to reboot the system and insert the iMac's DVD and run the Disk Utility from there. The error message received was:

The volume Untitled was found corrupt and needs to be repaired. Error: This disk needs to be repaired. Start up your computer with another disk (such as your Mac OS X installation disc), and then use Disk Utility to repair this disk.

I have the DVD with me, but the DVD-ROM isn't working. I have two non-Mac laptops with working DVD-ROM drives and all of them are on the network.

Is there a workaround to fix this problem?

Answer 1

There are a couple of options for trying to repair the file structure without another OS X boot disk available:

Try rebooting the computer with the Shift key held down. This invokes "safe boot" mode, which runs a disk check-and-repair as part of the startup process. Then run Disk Utility, run a Verify Disk, and see if it reports any problems. BTW, safe boot also disables some OS features, so you'll want to reboot again normally (i.e. without the Shift key) before using the system.

If that doesn't work, you can try the single-user mode option: reboot with Command and S keys held down, and it'll start to a full-screen command-line interface. Run the command:

fsck -fy

It'll run a full filesystem check and attempt to repair any problems it finds. If it fixes anything (it'll print "***** FILE SYSTEM WAS MODIFIED *****"), run it again since it may not find all problems on the first pass. If it reports "** The volume (whatever) appears to be OK", restart it normally with the reboot command.

If it reports problems it can't fix, or is still trying to fix problems after 3 or 4 tries, there's something seriously wrong and you should start thinking about backing up everything you want, erasing the drive, and starting over. 'Course, it'll be hard to reinstall the OS without an optical drive...

Answer 2

You can put the DVD image on a USB key and boot from that. You should be able to do that using one of the PCs. Google for the details, I don't have them to hand.

Answer 3

Does the iMac take the same DVD-ROM drive as a standard PC? If so see if you can borrow one from somewhere (or buy a new one that works) then you could just swap the drive over (to fix the DVD-ROM on your iMac) to then continue the repair.