I know that there are many threads about resetting/retrieving an admin password, but bear with me please and I'll explain why they don't work for me.

I recently moved in to a property only to find that the previous tenant had left behind a mid 2007 iMac - great, right!? No. The iMac works... as a CPU. The screen has been smashed up and has only a faint light emitting from the lower left corner so I have had to resort to buying a Mini DVI to VGA (which works perfectly as I'm currently on it on a guest account). This is where it gets a bit more complicated though. I wish to reset the iMac, but cannot without using the UIs accessed through reboot - when I access these (CMD+R, CMD+S, etc.) the external display isn't recognised so I go completely blind as to what is happening. I have read a few threads that say resetting an iMac is complicated, so I have thought about just creating myself a new administrator account, deleting the old one and all of the files with it - but without the old admin password, I can't do that - again, all threads resort to UIs accessed via reboot which I can't VISIBLY access...

So how can I reset the admin password without a working screen?

2 Answers 2


Simply create a new admin account by reinitiating the OS X Setup Assistant:

Boot to Single User Mode by holding S on startup with the external display attached.

Wait a few minutes and then enter ("blindly"):

mount -uw /

wait a second or two and then enter:

rm /var/db/.AppleSetupDone

In Single User Mode the US-en keyboard layout is used. If you have a non-Apple or a non-US-en Apple keyboard you have to adapt the input.

After the restart the OS X Setup Assistant opens and you can configure your Mac. Go through the steps of creating a new admin account.

After logging in on the new admin account, go to the Users & Groups preference pane. Select the old account(s), press the minus button for each and delete all files associated with them.

  • I tried that and it doesn't seem to work Dec 13, 2015 at 22:31
  • @LyndonHaslam which kind of keyboard do you use? US-English?
    – klanomath
    Dec 13, 2015 at 22:35

Do you have access to a second Mac with the same I/O bus (Thunderbolt or FireWire)? You can put the iMac into Target Disk Mode by holding down the T key when booting. The second connected Mac can then be booted, holding down the Option key to allow you to select the target disk. Make your modifications, and shutdown your booted Mac then reboot the iMac in TDM.

Ref: http://www.macobserver.com/tmo/answers/how-to-use-target-disk-mode-to-boot-from-another-macs-hard-drive

  • 1
    Note that you'll need to use a combination of Target mode and Recovery or Single-user mode to do a password reset on the iMac. Dec 13, 2015 at 19:06

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