Do you have the profile you exported from old computer? I do not know Mac, but use the file management software to view the Mail\Local Folders folder of that extract. The local folders should be there. If not, they were not captured when the transfer was made. Local folders can not be subscribed because they are not part of an account.

Hi David. Thanks for the quick reply. I'm not sure if the old profile transferred. I did have to download a new version of Thunderbird and I set up my account that way. Unfortunately, I don't see the many emails that I had stored in multiple folders. Perhaps they are on my Hard drive somewhere? I just did a search Mail\Local Folders on my MacBook Air hard drive, with no results.

Not sure what to try next. Thanks again. Taylor

The files would have been on whatever you copied from the old PC. I was hoping you might have it on a USB stick. The current machine would not have it.

I thought that those files (folders with old emails) would have existed on the Mozilla server and I would be able to subscribe to them once I set up my new Thunderbird account on the new mac.

Guess I was wrong...

To any Mac users (not sure about PC's)... I suggest doing a direct computer to computer or external HD transfer when replacing computers and not using the Cloud transfer. Cloud transfer works good on phones and tablets, but I've just learned the hard way that it's not a compete transfer for a computer.

Thanks again.

When I transferred all the data from the older Mac to the new Mac via iCloud, and set up my new mail account (IMAP), the folders did not download into the program.

I'm not sure but you still can try the following search since you used iCloud for your transfer and maybe your Local Folders are still in the cloud: open a Finder window and verify in the left pane if you can see "iCloud Drive". If you can select it maybe you will find Thunderbird"s Local Folders somewhere in one of the iCloud sub-folders as shown in my first screen shot.

If you can localise "Local Folders" in iCloud Drive: go to Account Settings > Local folders > Account Settings > Message Storage > Local Directory, click on "Browse..." and navigate to ..../Library/Mobile Documents/.... (second screen shot), select Local Folders, click on "Open". Thereafter Thunderbird will prompt for restart and I hope you'll recover your old Local Folders.

Local = only on the computer, not on a server

Did you make any back-up copies of data on your old computer?

I do not know if direct transfer would have copied Thunderbird files. It may not copy items from the user library, where Thunderbird data is stored. My memory says that it does not.

Thanks for clarifying this Rick. I do have a backup, however it's from 2022 which is the last time I did a backup, as I mistakenly thought that that iCloud would eventually transfer all my files..I was wrong (again!).

So I could possibly retrieve the Local Tbird files, though they would be missing many emails from the past few years, but may still be worth retrieving.

Needless to say, I will now be using TimeMachine again to regularly back up files on my new Mac.

Thanks again.

Local = only on the computer, not on a server

Cloud is no server, or am I wrong?

Hi Mapenzi. How do you mean? Is iCloud an e-mail server? No. But Apple has e-mail servers for iCloud accounts. iCloud is usually a sync store, but has some use as a file server too. For most people most of the time, it should not be treated as a server.

Apparently, Taylor used an Apple utility to transfer files via iCloud. Taylor, correct? I am not familiar with it. I have always used a direct connection. Another assumption: the utility did not copy all the data, only data in certain folders. A third assumption is that Apple does not expose copied data to users during this process.

All these assumptions could be wrong, so I would follow your suggestions. Taylor, do you see files from your old computer in your iCloud account?

Hello. I do not see Thunderbird files in my iCloud account. After further research about Thunderbird, they clearly state that they do not allow files transfers via the cloud as this is too risky.

In the future, I'll still use iCloud to transfer data between phones and tablets (though not Mozilla/Thunderbird files), but for computers, I will always transfer directly from computer to computer.

Thanks again.

I believe that the advice is not to make a cloud location the primary storage location for Thunderbird files. Using iCloud as an intermediate location when transferring files should be fine. If you had manually copied your Thunderbird profile to iCloud, then copied it to your new computer, everything would have been fine.

Back-ups are always necessary, not optional.  :)

Hi Mapenzi. How do you mean? Is iCloud an e-mail server? No. But Apple has e-mail servers for iCloud accounts. iCloud is usually a sync store, but has some use as a file server too. For most people most of the time, it should not be treated as a server.

You are right. I forgot that iCloud is also a server for @iCloud.com email accounts. I put my Local Folders in iCloud to be able to read them in different Thunderbird profiles.