The best utility on Mac by far. I was having this exact same issue on my reinstalled Mac mini after a big hard drive update and I found the easy bit of the link cured it immediately
This is the extract
"Or, you could go into Users & Groups in System Preferences, click Login Options, and change Display login window as: Name and password. Go into /System/Library/CoreServices and open Directory Utility. Click the lock in the bottom left of the screen and enter your password. In the Edit menu, select Enable Root User and enter a password.
Log out. When you get to the login screen, enter "root" (no quotes) as the user and the password you just selected. Once everything has loaded, open the Terminal (located in /Applications/Utilities, or just press Command-Shift-U to open the Utilities window) and type:
chmod g+x /
Note the space between the x and the slash.
Logout. Log back in as your usual user. Everything should be working now.
Go back into /System/Library/CoreServices and open the Directory Utility again. In the Edit menu, select Disable Root User. Close the program, and you're done. " [Joshua Brown]
I hope I'm allowed to do that but that message was getting so frustrating and it has saved me a couple of days redoing everything on to (probably) find myself back here at the end!