OK, thank you. Took a bit longer since I had to reinstall Hazel to be able to access this. I don’t think it’s linked to the rules though, since the problems already arise before I reimport the rules. Even just importing the licence works, but is somehow half forgotten (it shows up in the menu, but the trial prompt at program start always appears).
Afterwards, uninstallation was as complicated as usual, since the HazelNotifier kept coming back, although I had killed it in the Activity Monitor.
Hopefully I’ll soon be able to enjoy Hazel again! Have a great week-end