Mail app not opening after adding a new account

Question

Level 1

11 points

Mail app not opening after adding a new account

Hello to all.

I have a problem with the Mail App. After an Apple update some time ago, Mail wouldn't allow me to access any of inboxes multiple email account.

I wrote some procedures to move new emails from the inboxes to a folder where I could at least read them.

This worked for a while, I reported this situation and waited for a possible fix, and nothing eventuated.

The other day I added an account I didn't add some time ago so I added it. Now Mail will not open at all.

I use Time Machine, well, I have Time Machine but yet to use it.

So my question is, can I edit any list or data file(s) to undo what I've done?

I'll have to drop back to view the post, can't get email notifications.

Thanks in advance

Pilot McBride

Senior, citizen, 1st Apple was an Apple ][+, //e, 27" iMac

Now Apple M4, 24GB, Sequoia 15.7.2

iMac 24″, macOS 15.7

Posted on Nov 21, 2025 11:49 PM

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Answer 1

AlWeir

Level 5

4,862 points

Nov 22, 2025 8:44 AM in response to PilotMcB

If Mail hasn't been backed up to TimeMachine then you will have to undo what ever the "some procedures" you wrote to move mail around in Mail or get hold of Apple Support. They might be able to undo what you did but for us that try to answer these questions is something only a person that knows the OS and a good deal about terminal to undo it.

You could try to delete the Mail Account(s) and re add them to see if that helps.

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Answer 2

AlWeir

Level 5

4,862 points

Nov 22, 2025 9:24 AM in response to PilotMcB

If you are playing with plists, back them up fist so if anything goes sideways you can put them back and about the only way you can really do that is leave them in the Trash and use the "Put Back" option if need be.

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Answer 3

PilotMcB Author

Level 1

11 points

Nov 22, 2025 9:18 AM in response to AlWeir

Thank you for your reply my friend.

In the over 40 years I've been using an Apple computer I've never had to use Support or Time Machine, but being the age I am (+70), things are slowing down quite a bit and, well, I chased the endless links for "Support", got lost so I came to the community to see if someone had a solution. It sucks to be getting on.

I did find a pList file I can play with so will try editing that (with usual safety precautions) and see what happens

I'll chase it again a little bit later, house still asleep (4am local atm) when the house wakes up.

Thank your again for your reply, really appreciate it

PMcB

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Answer 4

PilotMcB Author

Level 1

11 points

Nov 23, 2025 9:24 AM in response to AlWeir

Thanks mate. That's about the only thing that has remained unscrambled after years of operations and anesthetics 😂.

Backup, backup, backup.

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