I recently switched to FF 67 and obviously using the same profile throughout multiple OS (Manjaro, Ubuntu and Windows 10 in my case) does not work anymore. The same applies to TB 68, I guess it's the same mechanism behind. I cannot comprehend what the devs thought here and I'm quite furious right now since this breaks up my whole setup. The official support page refers to Firefox Sync in this case, which I'm actually using, but that covers only a small portion of the now missing stuff. I cannot sync the current session, add-on settings, cookies, site preferences (like allowing cookies for certain sites), many settings (default search engine, telemetry etc.) and much more and for Thunderbird it doesn't work at all. I found here - https://support.mozilla.org/en-US/questions/1260190?mobile=0 - that it's apparently possible to restore the old behaviour by deleting compatibility.ini but I'm not sure if this breaks things in Firefox or Thunderbird, I obviously don't want to lose my bookmarks, open tabs or other stuff. How risky is this and are there alternatives? Many thanks for helping me.