Oh you should not need to touch them.
If you want to backup torrent progress and settings those files are in user/yourusername/AppData\Local\qBittorrent and user/yourusername/AppData\Roaming\qBittorrent
That is useful if you for instance need to reinstall Windows and want the torrent progress saved so you don't need to re add those.
What I meant by my comment was that in my case I had a bad disk drive without noticing it, qBittorent tried to access that drive and froze.
I wanted to keep the settings and progress. Deleting the directories above solved it for me.
I think those directories should be deleted during a successful uninstall of qBittorrent, but if they are not you could try deleting them yourself.
Or just wait for the dev to answer
