macOS Mail app crash repeatedly with 'Database write block nested inside a readblock.'

[Polgs]

Mail app on macOS Catalina spent a long time (about five mins) shutting down and now crashes every time I try to start it. The crash report includes the following:

Application Specific Information:
dyld3 mode
*** Terminating app due to exception while holding database lock 'NSInternalInconsistencyException', reason: 'Database write block nested inside a readblock.', userInfo: (null)
abort() called

I have tried booting into Safe Mode but that didn't fix the issue.

 

[0128672]

Have you run Disk First Aid?

 

[Polgs]

Have you run Disk First Aid?

I rebooted into Recovery Mode and ran First Aid on the base drive and Macintosh HD and Macintosh HD - Data. All ran with no errors. Rebooted into normal but Mail crash still there.

 

[0128672]

I rebooted into Recovery Mode and ran First Aid on the base drive and Macintosh HD and Macintosh HD - Data. All ran with no errors. Rebooted into normal but Mail crash still there.

I found a possible fix on an Apple discussion forum, which I hope will help you. I realize it's not exactly the same error, but worth a shot.

I moved the entire Mail folder to trash from ~/Library, did a restart and launched Mail.

That worked!!

Mail rebuilt my mailboxes and folders and populated them with my mail with no problems. No "out of memory" message and no Mail application crash. Woo!

Mail app crashes every time on Catalina - Apple Community

discussions.apple.com

 

[Polgs]

Thanks Namara for your help in finding a solution.

I called Apple Support and we disabled all my mail accounts (I had 21 from five different providers). System Preferences -> Internet Accounts. macOS Mail then started normally, without the crash but, obviously, no e-mail accounts. Then re-enabled the accounts in groups until we found the culprit that was causing the crash. I logged into that account via its web portal and checked that I could read and move e-mails without error. Then re-enabled that account on the Mac and macOS Mail started clean and didn't crash. And it's been working ever since.