Unable to remove login item from Users & Groups startup list

Question

I have an item in my "Login Items" list (System Preferences > Users & Groups > Login Items) that refuses to be removed. When highlighted, the minus button grays out. The "hide" toggle is also grayed out. There is no option in this specific app to disable load on startup. Why is it showing this way and is there a general way (override) to remove such apps?

Answer 1

For some reason, Content Manager Assistant added the login item to /Library/Preferences/com.apple.loginitems.plist instead of ~/Library/Preferences/com.apple.loginitems.plist.

I was able to remove the login item by deleting /Library/Preferences/com.apple.loginitems.plist and restarting (logging out and back in wasn't enough).