Check settings : View > Folders > select 'All' Uncheck any other options selected.

re :That account still appears in the settings list I presume you mean it is showing in the 'Account Settings' - please state if I'm wrong.

re :two new folders have appeared in the displayed folders list. One is popstate-1.dat which has appeared as a sub folder in another account (below the inbox, sent, etc folders). The other is a totally blank folder (unnamed) at the same level as the main account folders.

Please post an image of the Folder Pane so it clearly shows this. Popstate.dat files are used in pop mail accounts - they keep a record of what has been downloaded, so they do not get repeat full downloads. they should not be appearing in the Folder Pane. It means a 'popstate.dat' file has been converted into an mbox file - weird but has been known to occur. This has to be sorted out in the Profile folders - so can you do the following.

Menu icon > Help > More Troubleshooting Information Under 'Application Basics' - Profile Folder - click on 'Open folder' button It should open showing contents of your profile name folder.

If you have POP accounts - click on 'Mail' folder

Please make sure you are using the View - details so I see columns: name, modified date, type, size Make sure you have also selected the checkbox to show extensions.

Post image showing all contents of the 'Mail' folder

Click on each pop mail account name folder and post an image showing the contents of each one. Make sure image clearly shows which pop account I'm looking at.

Back in Thunderbird In Account Settings select 'Server Settings' for missing account Bottom right - locate 'Local directory:' Make window wide enough so you see all the text in 'Local directory:' please post image showing what you see in 'Local directory' as this will say where it is currently pointing.

Hello Toad-Hall

Many thanks for the reply.

I confirm I meant Account Settings

The images you requested are attached - I hope they help solve the problem.

Apologies for the complex set-up - long story!

Please let me know if you could do with more info.

The account at the top in 'Account Settings' 'Local Directory is pointing to the account 'mail.etg.me.uk'

In the profile folders account' mail.etg.me.uk' has: massive Drafts folder which really should be compacted unless you do have a large email saved in it. The Inbox is empty. The 'Sent' folder has a load of emails. Trash has something but not much. The 'popstate.dat' file is missing, so there is no file keeping a record of what has been downloaded. It should have auto created this.

Are you certain this is the correct account name. In Profile, there is another account called 'mail.estg.me-1.uk' It has been in use and has a lot of mail in Inbox Yet this account email address @estg.me.uk is not displaying in Account Settings. Find out if this is the account you are looking for .

In Account Settings 'Local Directory is pointing to the account 'mail.etg.me.uk' click on 'Browse' It will open showing the account it is pointing to go up a level to the Mail' folder then select 'mail.estg.me-1.uk' click on 'Select Folder'

Then do the bit below.

In profile folder account : mail.tesg.vispa.com It has a popstate.dat file dated 29/08/2022 size 1 kb - this is the one it is using.

Below - It also has 'popstate-1.dat' and 'popstate-1.dat.msf' - this is what is causing that file to appear in that account in Folder Pane.

Menu icon > Help > More Troubleshooting Information Under 'Application Basics' - Profile Folder - click on 'Open folder' button

Exit Thunderbird now this is important click on 'Mail' folder Click on mail.tesg.vispa.com Delete : 'popstate-1.dat.msf' Delete: 'popstate-1.dat'

Restart Thunderbird and report back on results.

If: In Account Settings IF 'Local Directory pointing to 'mail.estg.me-1.uk' then displays the correct folders in Folder Pane, we know which is the correct account, but now it is now assigned to the wrong mail account/email address.

Therefore it looks like you have created additional identities.

Reset: 'Local Directory to point to the account 'mail.etg.me.uk' then click on 'Manage Identities' button Select the mail account which uses correct email address *@estg.me.uk Click on 'Set Default' Click on 'Close'

Does that top mail account in Account Settings now show the 'Local Directory:' pointing to 'mail.estg.me-1.uk' ? If yes, restart Thunderbird and you should have the corrrect mail account using correct folders.

Many thanks for the detailed info.

I'm afraid I perhaps lead you astray by not explaining more about my 'complex' set up. In fact the anrg and etg accounts are sort of dummy domains giving me personal email addresses, incoming emails being forwarded to/by estg.me.uk so mail.estg .me-1.uk is the valid incoming mail from these accounts (mail.estg.me.uk is all dated the original date I set up Thunderbird so it seems I made a mistake back then). Thus this was not the solution to the missing account problem. However, it did lead me to looking more closely at Account Settings where I then found the error I should have found when the problem first arose. The 'Server Settings' in etg should be mail.etg.me.uk (of course!) but just 123 was in there. I certainly didn't change it when the account disappeared so how it happened I haven't got a clue but all is working again now with nothing lost.

'popstate-1' was removed as you suggested.

Many thanks for all your extensive advice and help.