did it delete it or just decide to not use it. Not using it has been going on since V68. https://thunderbirdtweaks.blogspot.com/2019/09/i-lost-my-profilemail-on-update-to.html

Yes, it chose no to use it, and I was vicitmized the sae way a long time ago - probably V68 since I've been using TB & FF since the beginning. I thought it may have happened because the size got so large it was impacting performance which has definitewly slowed down over the years?

My situation this time is even more complex in that I'm in the middle of migrating from a 10 year old 64b Wins 10 computer to a 64b Wins 11 computer. I had just installed both TB & FF in the new computer when the TB update occurred, and I've lost operating access my Contacts, mail and Bookmarks. Are there clean, easy ways to accomplish these migrations and keep both FF & TB profles so I don't have to start from scratch? Or is that not advisable because the profiles size has gotten too large for performance?

Appreciate any help or advice to make all this happen - thanks!!

Mike

If the profile is still intact on the old pc, and if the profile is in the default location, the simplest solution, and the safest (in my opinion) is to copy the c:users\<yourid>\appdata\roaming\thunderbird folder to the same location on new computer (do this when TB is not running on either computer, but already installed on new PC). That gives you a 100% profile transfer. On restarting TB, the profile will be right where you want it.