Hello, I have had this issue since at least 2022 starting with version 102.4.1. I am currently running 128.1.0esr on OS 14.6.1. I figured I would post again, as it has been a few years and the previous posts are now archived, to see if any new solution options are known. In short, Thunderbird runs perfectly fine in troubleshoot mode. When launched normally, it locks up as soon as it checks for new messages, I get the spinning beach ball, and I have to force quit to close it. Letting it sit for an extended time has no impact. Screenshot of status when it locks is attached. If I start in Troubleshoot Mode it works normally. No problems at all. I don't appear to have any add-ons or extensions running, so I don't understand why this is fixing things. I've just been running it in troubleshoot mode for years now, which is fine, but annoying. The only themes, extensions, or add-ons present are "light," "dark," and "system theme -auto." Nothing else. I had read a previous post about disabling access to Contacts in System Preferences, I tried that, no luck. I also deleted all add-ons and extensions files, and folders. Folders were empty, no change. Any other theories?