I can't really recomend this add-on at all. The developer blames the Firefox bookmark API, however they still leave the issue in that has the potential to cause complete loss of bookmarks, instead of disabling it all together. Being able to say you are cross platform doesn't do you any good when one of those platforms has such a breaking bug like this. Atleast a warning within the app itself would be nice, and an automated local backup of your bookmarks(instead of a manual one) would be very helpful too for when the addon decides to blow away half your library.