Apple Mail export/import corrupted my email by copying the same one repeatedly

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Apple Mail export/import corrupted my email by copying the same one repeatedly

On an old Mac I had a mailbox in Apple Mail's "On My Mac" section. The mailbox had 42,065 emails in it. I wanted to transfer this to a new Mac. I exported the mailbox on the old computer, transferred the resulting .mbox folder to my new computer, and then imported it in Apple Mail on the new computer. I glanced at the number of emails and saw that it was 42,065. I thus assumed everything was fine and deleted the mailbox on the old Mac and also deleted the exported .mbox folder.

However, I then noticed that all 42,065 emails in the mailbox on my new computer were identical. Either the export or the import corrupted all of my email! Unfortunately, I had no Time Machine backup on my old computer, and the .mbox folder is not in my Trash since I removed it using rm in the Terminal app. As of now, I believe I have thus permanently lost a lot of my emails! Any suggestions?

(Note this question does not regard macOS Monterey, but I was forced to pick a topic to post this question. I couldn't find Apple Mail in the list.)

Posted on Jan 8, 2022 4:02 PM

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Answer 1

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ash5791 Author

Level 1

8 points

Jan 9, 2022 4:56 AM in response to lllaass

Thank you for the suggestion. I ended up finding an old Time Machine backup, dug into the ~/Library/Mail folder there, and found the mailbox I had lost. I directly imported from that in Apple Mail, and it worked. So I got all my emails back!

Note I also had trouble exporting/importing another mailbox. I tried 4 times, but every time the import step ended with a warning message stating that some of the emails couldn't be imported. Indeed only about half of the 26,000 emails in this mailbox were getting imported. I again imported directly from the corresponding mailbox found in my old Time Machine backup, and that worked correctly. Seems there is a bug in the mailbox export, as the import did work in two cases from different mailbox folders (with otherwise the identical emails).

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Answer 2

lllaass

Level 10

210,423 points

Jan 9, 2022 3:21 AM in response to ash5791

First I would go to Mail app>Mailbox Menu and and the bottom is Rebuild. Click 0n that and see if that helps.

Next I would drill down into your Library folder and see if the messages are actually duplicated.

Here is where my Gmail messages are located in my Mac in Monterey

The V9 seems to be for Monterey and there are lower V number that seem to be for older messages.

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Apple Mail export/import corrupted my email by copying the same one repeatedly

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