I have Thunderbird 78.1.0 running on Windows 10 1909. The other day I noticed that when I opened TB the tabs for emails I had saved "open" were blank. If I opened a new email message it opens blank as well. I can use the reply/forward icons and it displays the contents of the email. Steps I've tried to resolve: * Bulleted list itemUninstall/Reinstall Thunderbird * Bulleted list itemDelete MSF files to rebuild message store * Bulleted list itemChanged from Open messages in "A new tab" to "A new message window" and then set it back Leaving "open messages in a new windows" does work. I can see the email just fine, not what I want though. I did restart TB in safe-mode disabling add-ons which does work. The only add-on I have is "Manually sort folders". If I restart TB in normal mode, disable the add-on, close and re-open TB I still get the same blank screen. Any thoughts? I have the troubleshooting report but would rather not post it publicly if possible.