Sorry to hear about this problem. Have you see the warning mentioned in the following article title:

Fix "The bookmarks and history system will not be functional" error message

If you don't see Firefox accumulating history and you can't move or delete existing bookmarks, you may need to take the steps mentioned in that article.

Thanks for the help. Renaming places.sqlite did the trick. I forgot to mention it in my question, but I had tried places weeks ago and it didn’t work, but maybe I didn’t have the right order of the steps.