Seems to freeze during connecting to IMAP and folder sync? Shortly after the first start in a windows session? Its not about IMAP: Most likely it’s a CALDAV problem/bug. Disable your remote calendars.
When Thunderbird starts it ignores already existing registry entries. That means, if you have had deleted an extension via UI and you did not change the registry entry (deleting or modifying) afterwards TB will not install this extension again. In other words: If you have once installed an extension via registry and you delete it […]
Debug it using the Developers error console. Try using ASCII (PEM) instead of Binary (DER) certs.
Basics: https://bytesandbones.wordpress.com/2019/09/30/thunderbird-gpo-admx Via Registry: HKCU\Software\Policies\Mozilla\Thunderbird\Certificates\Install\1 = “mycert.der” or Software\Policies\Mozilla\Thunderbird\Certificates\Install\2 = “\\MYHOST\Users\username\mycert.pem” or Software\Policies\Mozilla\Thunderbird\Certificates\Install\3 = “C:\CERTS\mycert.pem” as REG_EXPAND_SZ. If you define only a file name without a path Thunderbird searches %USERPROFILE%\AppData\Local\Thunderbird\Certificates%USERPROFILE%\AppData\Roaming\Thunderbird\Certificates for your files. Via GPO: Use the user branch. Define full path file location or file names only. If you specify only a file […]
Add your custom header. Do a folder repair. Thats all.