Im not sure if this just started with firefox version 80 onwards but i use an addon called livemarks which adds live bookmarks to firefox such as news feeds etc
I am using ccleaner version 5.63.0.7540 (and have done for a long time without issue) but now when i run it,it wipes out my live bookmarks that i have on firefox
I dont recall it happening on older firefox versions so im guessing something changed
I dont want to try a newer ccleaner version as i am happy with this version (apart from this issue of course),plus i dont know if it would make any difference or not