On 02-Nov-24 my Thunderbird installation on a windows 10 PC and a separate installation on a windows 11 laptop both crash on start up with no ability to start in safe mode etc and therefore no way of diagnosing. As a temporary measure on my PC I have put all the T-bird files in a safe place deleted the application and re-installed a fresh application with a new profile and the added back some of my email accounts. It is not ideal because all my preferences, tags etc have all gone and some of the new defaults settings on the fresh installation are not good. I would like to be able to go back to my old profile with a version of T-bird that works. Does anyone know what was going on on 02-Nov-24 that would have caused this? How can I re-instate my old profile?