Sorry for dragging this old thread up. But of the numerous threads covering troubles with the Apple Mail plug-in this one’s title is describing my case the most accurately—and first and foremost I did not want to start just another topic about this subject.
Okay, I meticulously followed all the steps Jim advised to take but failed at the last one. Although I deleted the old mail bundle, re-installed it and gave DEVONthink the rights to do virtually everything it wants with my Mac I could not activate the plug-in. Restarting the Mac didn’t help either.
I always get prompted “Incompatible plug-in is deactivated”:
Additional info: My Mac runs on macOS 10.14.6 (18G95) and there is no DEVONthink Pro Office 2 around anymore that might interfere.
Any idea what is going wrong?