Ifixit password

@Allan Jones brings up a good question. If you purchased a used Mac and you did not perform a clean install of macOS, then it may indicate a previous owner may still have control of the Mac. Even with a clean install of macOS a previous owner may still retain control, although you will usually see some sort of message or notification that the Mac is being managed (may not appear for days or weeks later).

If you cannot reset the password using the link I provided earlier, then you can first try the simpler option of just using a Time Machine backup to restore your account as @John Galt has suggested.

Otherwise you will most likely need to perform a clean install of macOS by first erasing the drive (or Volume Group) before reinstalling macOS & restoring from a backup. You can also perform a clean install if you have access to another Mac running macOS 10.15+, by "Restoring" the firmware which resets the security enclave and pushes a clean copy of macOS onto the internal drive.

Revive or restore an Intel-based Mac using Apple Configurator - Apple Support

Revive or restore a Mac with Apple silicon using Apple Configurator - Apple Support

How to reinstall macOS - Apple Support

I hope you have good backups since there is no way to access the data on the internal drive without being able to authenticate to the Mac even when booting into Recovery Mode or Target Disk Mode. If this Mac was purchased used, then none of these steps may work, or may only work for a short time.

Did you try Old Toad's suggestion?

Boot into the Recovery volume (boot with the Command + R keys held down  - Intel Macs) or  (How to Boot an M1 Mac into Recovery Mode), select Disk Utility and run First Aid on all available volumes. Reboot normally and see if that helped.

If not reboot into the Recovery volume and reinstall the system. It will not affect your user data.

In addition to what Old Toad suggested, you can also completely wipe/erase your internal drive from Recovery Mode and reinstall a clean system. But this will erase everything so before erasing, make sure you have reliable backups to restore from.

You have provided little information about how you have configured your Mac. Do you have any of the following:

• Virtual machines, other non-Apple operating systems
• Security packages not from Apple
• Firmware password
• Full disk encryption
• Also, have you ever seen this login window before
• Finally -- who else has physical access to your Mac? We have had posts here from people whose Macs were compromised like this when others in the house or apartment had physical access and changed things. Are any other users sharing your Mac?
• Does your Mac have remote access or Sharing set up?

Boot into the Recovery volume (boot with the Command + R keys held down  - Intel Macs) or  (How to Boot an M1 Mac into Recovery Mode), select Disk Utility and run First Aid on all available volumes. Reboot normally and see if that helped.

If not reboot into the Recovery volume and reinstall the system. It will not affect your user data.

If you have a Time Machine backup, now is the time to use it:

Restore your Mac from a backup - Apple Support

The picture you posted looks like a login screen for a different operating system.

If you are using a wireless keyboard, please try any USB wired keyboard (they're VERY cheap). Remember to continue to hold down the Shift Key until the computer fully starts up when doing a Safe Mode restart. This can take up to 10 minutes so be patient.

That could be malware.

Try to use Malwarebytes for Mac to remove anything:

Malwarebytes for Mac - Malwarebytes.

Jack

In order for us to really help at a bare minimum we need to know the model year of the iMac and the version of Mac OS installed. You can easily find this info by clicking the in the upper left of the display and selecting About This Mac .

Please attempt by restarting in Safe Mode, instructions are in Safe Mode.

ericfromhurst wrote:

Suddenly, in the last couple days when I try to start up my 2020 iMac I get a box requesting an account name and password (not from Apple). There is a logo I didn't recognize that I was able to trace to ifixit. So ifixit is asking me for account name and password, which I don't have. Their website couldn't be less helpful. Can anyone help? My iMac us completely unusable until I solve this.

That is not an iFixit logo and iFixit doesn't even offer any software products -- it's a hardware site that basically sells special screwdrivers and hardware tools used for users self-repairing their Macs and iPhones.

You can try resetting the password:

https://support.apple.com/en-us/HT202860

Did you give anyone access to this Mac or have it repaired? Sounds like someone at least changed your login icon and maybe your password.