Profiles that are not in use can be safely removed.

Hi David. Thanks for the reply. How can i find out what is in these profiles? What about the profiles that are in the list but not in About: profiles?

I'm not sure where they all came from 73t is 96 kb from 10 Jan this year (not in use) gas is 824 Mb from 10 Jan 2023 (in use) 29az is 3.42 Gb from 28 Jan 2023 j9q is 16.4 Mb from 28 Jan 2023 7f6 is 11.4 Mb from 12 Feb 2023 (not in use) I changed computer at the beginning of january 2023 . I suspect the 3 Gb file may have been from my previous computer and don't want to lose emails if it is

Assuming they are not corrupt, you can use each by - exiting TB - click windows key and 'r' key and then enter thunderbird.exe -p which invokes profile manager. click the create profile button, then next, then enter a name (e.g., profiletest), and then click the browse button to locate and select one of the profiles to view. Repeat that for each profile.

Thanks, David. I’ll give it a go. The large file and a small one WERE from my previous TB on my old computer and have emails from the beginning of 2019. I don’t suppose there’s any way of merging two?

you're right; you would need to isolate the various message folders and then copy to current profile's local folders folder.

Is that do-able?

I wouldn't say it otherwise. Thunderbird is just a bunch of files and folders that can be moved and copied. Look for the patterns (e.g., INBOX and INBOX.msf) as those are the message folders. As long as you COPY them to profile, you lose nothing and if you make a mistake, you can start over. Do all that with TB NOT running.

One of the old profiles is from 2019 and is 4.6 Gb in size. Is it normal for them to get so big?

Well, it's not uncommon if you have a lot of messages and attachments and seldom compact folders.