Recover Missing Mailboxes After Big Sur Update

In your user folder is a folder called Library (sometimes hidden so look up how to access it) and in there is Mail. In Mail is a folder that is called V with a number. In there are a bunch of sub-folders and you need to look around in them to find the folder you want.

I just used Time Machine to find the folder from my last backup. I stupidly forgot to backup immediately before upgrading, but it's only a week old. I may be missing a few e-mails, but not too many. I selected the Receipts.mbox folder, pressed the Restore button, saved it to my desktop, then in Mail I selected the Import Mail... menu item in the File menu, selected Receipts.mbox, and it got imported into an Import folder in Mail. I then just dragged it out of that folder and back into my main Mail list.

This is considered "solved?" I HAVE 92 FOLDERS CALLED "LIBRARY." CAN SOMEONE PLEASE SHARE THE PATH TO THE FOLDER THAT WOULD HAVE BEEN REMOVED FROM EMAIL DUE TO THE BIG SUR UPGRADE AND, ONCE LOCATED, TELL US HOW TO PUT THOSE BACK INTO OUR EMAIL???? I HAD NUMEROUS, ABSOLUTELY ESSENTIAL FOLDERS SAVED THERE!

I have dozens of mail folders which have disappeared and having moved into a new home a week ago, have no recent Time Machine backup. The folders and messages are still present when I access mail on my iPhone fortunately, but this is unacceptable from Apple. Clearly a bug that needs to be fixed ASAP.

Just finished Chat with Apple Support. Go to settings, internet accounts. Delete the Mail account with the issue, open Mail, close Mail, add back the problem account. Fixed my issue, now just have to wait to download a few thousand emails.

One of my email accounts still showed up in mail after the Big Sur update but all 21 folders in the account were empty. I right clicked on the mailbox name and clicked on " synchronize (mailbox name)" and all of the messages showed up in the folders. I hope this solution helps someone.

Hi, Not sure if this has been answered for you but......

In Finder select Go from the main menu to get the drop down menu and then press the alt key. The link to Library should appear between the Home and Computer entries. Select it. You will then be able to scroll to mail and in there the Vx folder containing all your mail. The directories are now named cryptically so you need to open them up to see what is inside them.

The full path is:

/Users/your_user_name/Library/Mail/V8

Good luck.

To answer the second part of your question.

Once you have found the file you want you need to use the File:Import Mailboxes.... function in mail. However, I could not find a way to get back to the Library folder once I had selected either the "Apple Mail" or 'files in box format" route (Can someone else offer a solution here?).

So I had to copy the entire Vx folder to the desktop and import what I wanted from there. Do not just drag and drop the folder as it will move it (not copy it) to the desktop and that will give you more problems with the mail app.

Hope that helps.

However, before you do all of this, I suggest you first login to your iCloud account for your Mac (or PC) and check your mail there. My archive file as there and in fact, when I looked around I found all my archive files on the Mac but under my iCloud mailbox entry. So I just added it back to the Favourites entry (I will now archive all my mail in the iCloud account no matter what mail address I have used).

It would help if someone at Apple could explain why the archive folder (or others) have gone "missing" from the favourites area. I used to be able to archive my old mails and the app sorted them into the respective email address archive folder but that is not happening now. It is still working on my iMac that can no longer be upgraded so Big Sur is not an issue there.

So be careful and check that the files are truly missing before importing and giving yourself more problems.

Well. . .it's not like I'm an expert. But I found my custom folders in the V8 folder within the library, and then used the Import Mailboxes under the File menu in Mail. The first option should be left at Apple Mail--not .mbox as you might think. Click through until you find the containing folder in the V8 folder and import. They'll be added to your Mail program under "On My Mac" under a sub-heading of Import. Hope that's the solution for you. Good luck!

Oddly, I also had a folder called Receipts that disappeared. It, and a bunch of sub-folders, all disappeared. This seems to be a bug.

I got this part... but how to put all the mails back to order?