When I tried to start Thunderbird this morning I had the attached image appear. Some background. Yesterday I installed a new drive into my computer (Windows 10). This involved changing the drive letters such that my thunderbird profile was now on drive E instead of drive D. I located the Profiles.ini file and changed references to drive D to drive E as shown here: [InstallC1263DE4EAE8A7E6] Default=E:\Users\Richard\Documents\Thunderbird Profile\8vg3bmxa.default [Profile1] Name=Richard IsRelative=0 Path=E:\Users\Richard\Documents\Thunderbird Profile\8vg3bmxa.default Default=1 [Profile0] Name=default IsRelative=1 Path=Profiles/movow05a.default [General] StartWithLastProfile=1 Version=2 After doing this thunderbird started and was OK – I was able to receive new emails. I don’t know whether sending new emails worked or not as I didn’t try to send any. But this morning I have problems. When I start thunderbird in Safe mode it starts OK – both receiving and sending. So perhaps I have a dodgy add-in. There are 5 entries in the extensions folder. I have removed all these, but now when I try to start thunderbird in normal mode nothing happens at all, the icon just flickers but there are no errors or anything else. Safe mode still works. I restore the 5 extensions, and now thunderbird does start normally, except there is an error message about the English (GB) Language pack - which is the second image below. I click enable for this, and get the same message for the other add-ons - which I also enable. After the last of these thunderbird restarts and appears to be normal. So it appears to be all solved - I don't need any help with this now, but thought my documentation of what has occured may be useful to others, as I was unable to find that any one else had had these problems. Regards Richard