I have an iMAP account I've had forever - always used Thunderbird (Win 7). Thunderbird just updated itself to 78.4.0 (32 bit). A couple of days after the update, the folders for my email account disappeared. I can see on my mailserver that the folders are still there. I have about 50 folders (plus ~7 folders that are defaults). If I right-click on my account in Thunderbird and choose "subscribe", I can see that all of my folders have somehow been flagged as not subscribed. If I add a checkmark next to any folder, and click subscribe, nothing happens - so the ability to "subscribe" is not working. If I reboot my computer, and launch Thunderbird, I can see all of my folders for a couple of seconds (when the app first loads), then they go away. Can someone please help me fix this?