I've used this for a while, but I just spent hours troubleshooting an issue that turned out to be this addon. I even went so far as to delete my entire Mozilla account trying to figure out what was going on.

The problem is that it removes every bookmark from every folder on my system and places them *all* into the default folder (in my case, the bookmark toolbar.) All 3,000 of them, in random order, in the toolbar, and empties the entire folder structure I've been using for a decade.

Which was then synced on to seven other systems.