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Beliblis

macrumors regular
Original poster
Dec 31, 2011
241
11
Hi all,

I upgraded Mojave to Big Sur yesterday. (2018 Mac Mini)
On first launch, Mail displayed the usual "updating database" message. No error messages, but: all Mails for all accounts are now gone.

I have a full backup (Carbon Copy Cloner), so I'm not breaking a sweat (yet). I tried resetting Mail by copying ~/Library/Mail, ~/Library/Containers/Mail and the "Mail" files from the Preferences folder for a second and third attempt, but the result is always the same.

I have several mail accounts, and they're all gone.
Several years of E-Mails, organised into folders. Everything is POP3 (I only use IMAP for my mobile devices).

What is the best way to overcome this? Is this a known problem?
A manual .mbox import could work I guess... but that wouldn't recreate my folder structure.
Besides – the folders inside ~/Library/Mail/V6 have cryptic names. So I wouldn't even know which folder to import for which mail account.

Could it be that the Mojave to Big Sur upgrade is the problem?
Better to do a incremental update Mojave -> Catalina -> Big Sur?

I'd very much appreciate your help with this!
I've been upgrading my Macs for nearly 2 decades now, always with a user folder transfer. Never had a problem like this...

Many thanks!
 

BrianBaughn

macrumors G3
Feb 13, 2011
9,694
2,445
Baltimore, Maryland
You probably have a great reason to use POP3 for Mail on your Mac but what you are going through is, for me, the #1 reason to use IMAP/Exchange and have zero local folders on the Mac.

I recently upgraded from Mojave to Monterey with no Mail issues…however no POP3 was involved…not to say that POP is the cause of your problem.

I don't have any great suggestions to avoid the work that you're probably going to have to do. I think first you might have to see if you can get the Mini to boot Mojave again, migrate (or boot, if possible) from the clone, and check to see if your Mail folders are OK.

If that works…you'll probably have to export your folders to MBOX for reimport into Big Sur. Another possibility would be to create a temporary IMAP email account with a duplicate folder structure of your POP or On My Mac email. Then you could copy the email from the POP/On My Mac folders to the IMAP account folders. Once the copying and uploading is done all you'd have to do is add the temporary IMAP account to Mail in Big Sur to bring it all in.

After going through all this you probably won't be using POP3 anymore!
 

Beliblis

macrumors regular
Original poster
Dec 31, 2011
241
11
Thank you for your answer.
Yes indeed – I'm using POP3 for a good reason. But I don't think that's the source of the problem: I have 2 IMAP accounts which are also gone since the upgrade.
Prior to the upgrade, the Mail folders were OK – so I can't see the reason to downgrade/migrate to check Mojave.

That said – I'll probably have to boot from my Mojave backup anyway, so to create the MBOX exports.

How is MBOX "structured"? Is it one MBOX per E-Mail-Account?
Or would I export each of the folders in my Mail folder structure into a separate MBOX? And can one MBOX export contain e-mails from different e-mail-addresses?

I doubt that I'd fully move to IMAP. It just doesn't 'feel' right, to leave years of e-mails with an e-mail provider. I appreciate it's a bit old-school these days. But some e-mails are too important/personal to leave them "in the cloud" forever.
Anyway – each to their own. Don't want to turn this into a POP vs IMAP discussion ;)
 

BrianBaughn

macrumors G3
Feb 13, 2011
9,694
2,445
Baltimore, Maryland
Exporting/importing mbox with Mail is squirrely and I just tested. I had a "Master Folder" and three subfolders. No mail in the master and only a few each in the subfolders.

I exported the Master Folder, clicking "Options" and including all subfolders. After re-importing, what I got was this:

Screen Shot 2022-06-13 at 11.35.36 AM.png


The emails for each subfolder actually end up in the nested "mbox" folders. It's workable, I guess.

Keep in mind that when exporting a LOT of emails it can take a while…and (for Monterey) there's no feedback on the process. The export folder will say "partial" in it's name until it is done. Quitting Mail will interrupt the process.
 
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Beliblis

macrumors regular
Original poster
Dec 31, 2011
241
11
Thanks again for your input / feedback. Had a day off yesterday and today, and took the time to try to understand Mail's library folders (User/Library/Mail). Which led to rethinking my mail approach.

A week ago, I didn't think I'd be happy to make the transition to IMAP – but I actually did. What I didn't know was:
I can run IMAP and still keep my old "On my Mac" folder structure in Mail. And when I move e-mails into one those folders, those e-mails get deleted from the mail server.

Transitioning/importing the .mbox files was a breeze: those local "On my Mac" folders inside User/Library/Mail/V6 were already nested mbox files anyway. So there was nothing to export:
I just restarted from my Mojave backup and moved my old POP Inboxes, Sent Items etc into some new local folders. Then deleted all POP accounts, restart into Big Sur and reimported all Mail.

Only downsides I can see so far:
  1. Now that I've converted my old "POP Sent Items" into a "mbox Sent Items" folder, I can't see a way of displaying them by "sent to".
  2. I can't do a search across ALL inboxes and "On my Mac" folders simultaneously. Not sure if this is because of my move to IMAP, or because of Big Sur?
    With POP/Mojave, I could enter a search term, and then select the search location: Inbox only, or everywhere
I guess it'll take some time to get used to. Especially the search thing. Time will tell...
 
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