Since updating from Windows 7 to Windows 10, Thunderbird has been acting erratically. At random times, it stops checking for new mail. If I then try to get it to check for mail manually, it freezes. It responds to some menu commands, but clicking anywhere in the panes (list of mailboxes, list of messages, etc) does nothing. Sometimes it opens a blank notification window, which I can only get rid of by killing it with the Task Manager. More often, if I simply close Thunderbird and restart it, it starts working normally again... For a while. The problem seems to mostly recur when I bring Windows out of sleep mode, but I'm currently running Thunderbird 38.2.0. I've tried disabling a few add-ons I wasn't really using; I'll see if that helps. I've seen it suggested that users with similar problems run Thunderbird with all add-ons disabled, but I've also seen it said that that's really only a temporary fix rather than an actual solution and I agree. Current list of enabled extensions: Add-on Compatibility Reporter 1.1.1 Add-on Update Checker 2.13 check Compatibility 1.3.1 Compact Header 2.1.0 Mark All Read Button 0.7.1 Minimize to Tray revived 1.1.2.1 Any other suggestions? Anyone else having the same problem? I've seen a few others with Windows 10 issues, but nothing that quite matched mine.