While running a restore function of a backup program I had to stop it. After that I noticed that most (all?) icons on my desktop and inside folders show small locks. The backup software company didn't help. They say it's a coincidence.
It's been several months already, but all the old folders and files still show locks. I checked the obvious file ownership settings. Everything looks normal. The account that I use has full rights and I'm able to manipulate the files, so the lock icons don't seem to indicate any restrictions, however they are still present.
Just to clarify, new files and folders don't have the locks.