Before I troubleshoot further, is anyone else have issues with URLs to Mail messages (Message-ID) not working in Catalina (such as the links sent to apps like Things or OmniFocus, or grabbed via AppleScript, which, when clicked, will retrieve the Mail message)? I get an error with every URL, " The operation couldn’t be completed. (MCMailErrorDomain error 1030.) Mail was unable to open the URL [link to message]"
newly created one or old existing urls?
It’s both. I found a pre-Catalina Things task to test it on. I also tested on a different email account, to make sure it wasn’t just one account, and have the same error there. I’ve rebuilt the mailbox, and removed and re-added the account, with no luck. I’m curious if anyone else has this, or it is just me.
I believe I’ve identified the culprit. I was using the MailSuite Catalina beta. Once I removed that plugin, things were back to normal.
I’ll report the bug to the MailSuite folks. Between MailSuite, MsgFiler, and MailHub, I hope somebody gets a Catalina plugin working properly, because the quick filing feature of each plugin is essential to my workflow.