Is this the procedure you used?
Boot into Single User Mode and remove a setup file
Restart the Mac holding down the Command+S keys, this will take you into Single User Mode and it’s Terminal interface
You’ll need to check the filesystem first:
fsck -fy
Next, you must mount the root drive as writeable so that changes will save:
mount -uw /
Now, type the following command exactly, followed by the enter key:
This procedure verifies the file system. You would have gotten warning messages if any problems were found with the file system. I'd expect some warning if there was a problem with the drive. It's still possible to have a bad drive with no warning messages.
The next step is to rebuild the accounts database. What version of macOS do you have? I'll have to look around for how. Rebuilding the database may have changed over the years.
How old is your mac? Harddrives start goin' bad at three to five years. You could get an external drive and install macOS on it.
Do you have backup? if no, and you need to recover your data. See this link:
backing up from the command line via single user mode.
https://discussions.apple.com/thread/8101803?answerId=32357328022#32357328022
R