Hi sign_up, sorry to hear about this problem. Could you check whether your Firefox is using a new profile? In a new profile, Firefox only discovers certain add-ons in shared folders or advertised in the Windows registry.

Profile Manager Page

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list one or more profiles. The newest one typically is named default-release and the older one(s) might be named default or a variation on the word default.

Each profile has one or more buttons at the bottom: please do not use Rename or Remove to avoid further problems.

Can you find a "Set as default profile" button for your previous profile? After setting that, you can exit Firefox and start it up again, but the history/settings in the current profile will not carry over after the switch.

Was that the issue?

Thank you for looking inito my problems. Unfortunately your solution does not apply to my situation: sine one year I have set up Firefox to always ask me which profile I want to use and I always use the same.

sign_up said

Thank you for looking inito my problems. Unfortunately your solution does not apply to my situation: sine one year I have set up Firefox to always ask me which profile I want to use and I always use the same.

Aha! So your desktop shortcut or pinned Taskbar icon Target is similar to the following:

"C:\Program Files\Mozilla Firefox\firefox.exe" -P

In the Profile Manager, do you see a new default-release profile listed, or only the profiles you had before?

After launching Firefox, if you open the Profile Manager page (about:profiles), can you confirm that Firefox actually used the profile you selected? It should be marked with the following:

This is the profile in use and it cannot be deleted.

Thanks again. As I said: one year ago I set up firefox to let me choose profile at startup and I always (try) to choose the same. For some reason I manage always get this question about which profile to use but I can't see the "-P" as I should in the pinned shortcut. But let's leave that at present. The main thing is as you say that with the upgrade to 67.0 I saw my two profiles but for some reason chose the wrong one. Maybe the profile I have used for a year was not colored in blue after the upgrade and I was not alert enough to discover it. And with the profile I did not use for a year now being the default I got the wrong add-ons as You described it. Thanks again !

So, you were able to switch profiles and now you have your stuff back? I hope that's what you're saying.