How to fix import errors in the Mail application?

I followed some of the information in this thread and fixed it very easily by simple unchecking Mail from all the Internet Accounts in System Preferences except for iCloud. I started Mail it started instantly with only 257k and then I right-clicked on the iCould inbox folder and selected Sync Mail with iCould. It went to work and did its thing. Lastly I brought back all my other internet accounts online. Easy peasy :)

Ok I need to confirm that starting up in SAFE MODE (hold down shift when booting up) will totally fix this.

1. Deactivate mail in ALL internet accounts in settings. That will import the fewest number of emails just to get the app running
2. Boot up in Safe mode (hold shift)
3. Start up mail and import to get it running
4. Reboot normally
5. Go to settings and turn on all of the internet mail accounts
6. Let it buld each account again
7. Drink a beer and rejoice

LMK if this works.

I was in the same predicament. I finally gave up and contacted Apple Support (in Sweden) and a very skilful and helpful guy helped me through the problem. To solve the problem I had to cancel all three mail accounts I have in System settings. Be sure that you have all data about your accounts stored somewhere or printed out so you can reregister again.

After that I started Mail app again and now it launched but of cource with very few data.

Then I registred the account from my internet provider (but leaving the two accounts which were private domains) and all of a sudden the import begun.

Then we tried to reenter one of the other accounts, but failed when using the private domain email adress. We then changed to the ”original” account (used for redirecting incoming and outgoing mails) which is from the same provider as in the first attempt. Now this account also showed up and imported all stuff related, but as the ”original"email account. The same procedure with the last account was successful, and now I’m very glad that everything is up and running.

So there is some some mismatch between Sonoma and my private adresses which I have to figure out with my domain service provider.

Of course there is a lot of things to sort out (layout, delete old stuff, move certain mailes to right folders etc) before all is back to ”normal” again.

It's a corrupted mailbox.

What worked for me was to go to Library/Mail, then in the current version folder, move any file ending in .mbox to a desktop folder. Re-import files a bit at a time after that.

This worked for me...

Restart in Safe mode and try again the import:

Start up your Mac in safe mode – Apple Support (UK)

Restarting in Safe Mode and rerunning Apple Mail worked for me. MacBook Pro with Mojave 10.14.6

Restarting in Safe Mode and rerunning Apple Mail worked for me.

MacBook Pro with Sonoma 14.3.

Thanks bevance!

Restarting in Safe Mode and rerunning Apple Mail worked for me as well. MacBook Pro with Mojave 10.14.6

Yes! The idea to go in and move all the account folders that contain the .mbox files was genius @Don_DYL!

I moved all the account folders (using Mail v10) out of the V10 ~/Library/Mail/V10/MailData folder to my Desktop and Mail reopened without trying to perform another failed import on startup.

Thanks for the great advice!

Restarting in Safe Mode and rerunning Apple Mail worked for me as well.

iMac 2019 with Sonoma 14.3.

Thanks bevance!

Hi iraayeed,

Thank you for using the Apple Support Communities! For this error, you'll want to ensure you follow the guidance below to free space on your Mac:

Free up storage space on your Mac

If you continue to receive the error, we recommend that you reach out to Apple Support directly to take a further look. Please reach out here:

Apple Support

Hope this helps!

Have a great day.

Moving .mbox files to desktop worked for me

Sonoma 14.4.1

Thanks

Starting up in Safe Mode works. Thanks!

Safe Mode etc etc etc worked for me June 2024 iMac Sonoma 14.5

Thanks!!

Richard

This is happening to me as well, and there is plenty of storage space on my Mac.

Maybe my Mail database is too big? Nearly 200k messages...

But it used to work well until yesterday, today suddenly an import is necessary (and since it fails, Mail is not running anymore).