I too am getting a UI freezing problem, always in the People tab - never in the Folders or other tabs.
This is on Ubuntu Mate linux, and I launch tonfotos from a shell, so that I can see the output. Interestingly, when the UI freezes, the program is still running in the background, scanning folders - I can tell from the shell output. It’s just that the UI won’t redraw. Sometimes it recovers after a minute or so, sometimes it doesn’t and I have to kill it (control-C from the shell).
Starting it again, it often will start up frozen, unless I’m fast enough to click over on the Folders tab, in which case it might recover. But… once I head back to the People tab, it will eventually freeze up again - sometimes with people that have a lot of face photos.
