Thunderbird ver115.8.0, Win11, 64bit Ten or so email accounts running on TB with a mix of pop3 and imap. When starting TB, it usually hangs and the only way out is to close using the X in top right. This is followed by the application wanting to report the problem to Windoze etc. Once I have canned out of this and restarted TB, everything goes well. I have default theme, no extensions or add-ons running. Cache is set to clear on shutdown. I recently deleted all .msf files. The status bar always shows one particular imap account during the hang (hang will continue until TB restarted) - that account is the first account listed in the mailbox tree in LH panel.