macosupgrade
My friend updated his 13" MacBook Pro to OS X Lion today. After upgrading he has been met with a login screen showing a single account, "Guest". This "Guest" account is password-protected and none of the existing passwords he used on the computer seem to work.
My friend had previously installed rEFIt on his computer, which apparently hasn't been updated for Lion yet.
I found this thread on MacRumors where a few other people are reporting the same problem.
Does anyone know of a solution?
It very likely got overwritten. The upgrade does nothing to back up what it considers "system files" and simply overwrites them with the latest version.
Another good reason to do a full backup before upgrading.
If you hover over the disabled option, a tooltip appears explaining that the guest account can't be activated with FileVault turned on:
This is because the new FileVault uses full-disk encryption that's decrypted by the login password of one of the users. As the guest account, by its nature, does not have a password, that would leave your computer completely unprotected. You can still create an account for guest purposes as a regular account though.
it has been noted that this hover tip may take some time to display and can be difficult to trigger for some people, but regardless of whether or not you can see the tooltip the answer to the question is the same
Best Answer
An easier way is to:
/Volumes/<your root volume>/Library/Preferences/com.apple.loginwindow.plist.That's it.