"[classify desktop]" was the first place where I tried to put it and initially it seemed to work, but half an hour later I was saddened to find out that the freezing was back. Then I decided to try with "system" partition, of which "sysutils" looked like the most suitable category and QtLockscreen held up smooth for well over a day, interrupted by a reboot due to curiosity caused by your post (I'm *almost* certain that I checked for typos after such traumatic disappointment ).