Catalina Mail app's badge icon constantly backwards

snail22 wrote:

My Mail app's unread mail indicator behaves very strangely... when I mark a message as read, the indicator remains at "1", and then goes away only if I mark the message as unread again. So it is constantly wrong, showing an unread message when there isn't one, and showing no unread messages when there is. Here is a video... you can see the dock icon's indicator is always backwards from what it should be.

http://everettwarner.net/images/screenrecording.mov

Restarting the Mail app fixes the problem, until a new message arrives. I've tried rebuilding my mailboxes, trashing plist files, etc. and nothing will stop this. Am I going crazy?

EDIT: it says I am running OSX 10.11 but that is because I selected the wrong computer... I am on a MacBook Pro running 10.15.4

Boot into Recovery (Command R) and from the dropdown menu: Utilities>  Disk Utility> run the First Aid on your Macintosh HD (and the "Macintosh HD-Data" volume as well if Catalina) If errors are found and repaired, run again until no errors reported.

Recovery: https://support.apple.com/en-us/HT204904

To trouble shoot further you can:

Try a SafeBoot https://support.apple.com/en-us/HT201262

Takes noticeable longer to get to the login screen, does a 5-15 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc. Login and test. Reboot and test

To sort various anomalies there has been success in reinstalling the Combo update on top of your existing macOS 10.15.4

Combo update macOS 10.15.4 https://support.apple.com/kb/DL2037?locale=en_US