Why is Mail saying DEVONthink's plugin is incompatible?

When Apple upgrades their operating system, it sometimes causes an incorrect report that DEVONthink’s Apple Mail plugin is incompatible. This often happens when upgrading to major releases, e.g., from macOS Big Sur to Monterey.

The first thing to try is simply reinstalling the plugin via DEVONthink 3 > Install Add-Ons.

If that doesn’t work, try this to have a fresh installation of the plugin…

  1. Quit Mail.
  2. Quit DEVONthink 3.
  3. If you haven’t already, enable Full Disk Access and all automation requests for DEVONthink 3 in System Preferences > Security & Privacy > Privacy.
  4. In the Finder, hold the Option key and choose Go > Library.
  5. Go into the Mail/Bundles folder and delete our .mailbundle file.
  6. Relaunch DEVONthink 3 and install the Mail plugin from DEVONthink 3 > Install Add-Ons.
  7. Relaunch Mail and enable the plugin via Preferences > General > Manage Plug-ins.

Note: The name of our .mailbundle file is correct as-is, even if it may appear incorrect for the current operating system.