re : I changed the account type from POP to IMAP,

just to be clear....You created a new existing mail account as IMAP. You cannot just swap the account server settings of a Pop account to server settings of an Imap account. It can cause all kinds of problems because the two use entirely different storage locations and methods.

On startup Imap accounts synchronise with server to show what is on server. As the copied mbox files from backup do not exist on server they would get deleted, so nothing would appear.

re : Is there a way of copying the emails from the profile back-up to the new IMAP acct

Whilst Thunderbird is closed. Access the backup. In the 'Mail' folder you will see your pop mail account name folders and 'Local Folders' folder.

Open the 'pop mail account name' folder to see contents. You will see mbox files (no extension). They have same name as folders eg: Inbox, Sent, Drafts, etc. mbox files contain emails.

You will also see index files, they have a .msf extension. They do not contain emails. Do not worry about them. You might have folders with .sbd extension. These would be present if you had subfolders and they may contain mbox files.

You can copy the mbox files and paste them into the 'Local Folders' mail account folder.

Start Thunderbird, those folders will appear in the 'Local Folders' mail account. You then have the option to leave those emails in Local Folders mail account because they are still stored on your computer and accessible and will not use any quota on server OR get copies uploaded to server so they appear in the imap account.

To get copies back onto server: In 'Local folders' mail account, highlight batches of emails, right click on highlighted emails and use 'copy to' choosing a suitable folder in the imap account. Use 'copy' not 'move' and do it in batches to ensure they get uploaded.

Please remember, Imap works differently to pop. You cannot rely on imap folders as a permanent copy in Thunderbird because unlike POP, Imap folders constantly sycnhronise with server to show what is on server, not the other way around. In effect, imap folders and server folders are one and the same. If you need to create a backup, make sure you have synchronised folders and got full copies downloaded. then exit Thunderbird and create a backup of the 'Roaming'/'Thunderbird' folder.

Info on imap accounts and synchronisation: https://support.mozilla.org/en-US/kb/imap-synchronization#w_configuring-synchronization-and-disk-space-usage

Thank you! Sounds good I have to go out but will get to it this afternoon. Again thanks.

Thanks, now that it is synchronized the local copies will or will not be deleted when they are deleted from the server? Thanks Chris

If you logon to webmail acount and delete an email - let's call it 'X', then 'X' will get deleted from server and also get deleted from the Thunderbird imap account folder.

If you delete any email let's call it 'X', which is in an imap account folder, then 'X' is deleted from the imap account folder and the server.

Assuming the same email 'X' (a fully downloaded copy) is in a folder in the 'Local Folders' mail account, then it will not get deleted. 'Local Folders' mail account folders do not synchronise with any imap folder nor server. They are a separate set of files stored on your computer. 'Local Folders' mail account is a very useful place to store copies of important emails or if you are reaching a full quota situation on the server and need to delete email off server, but want to keep copies of those emails. You just have to be certain you are keeping copies of fully downloaded emails and not just the headers.

Does that include Archives? They are not stored on my computer?

From what I just read I can temporarily switch my IMAP 365 account to POP download and manually back them up (archive) then change the account back to IMAP, is this right? Chris

re : I can temporarily switch my IMAP 365 account to POP download and manually back them up (archive) then change the account back to IMAP, is this right?

If 365 account allows POP, you can select that option. But personally I'd use the imap account because you have already got access to the server via your imap account, so you can subscribe to see any folder.

The POP mail account would need to be set up as a completely new existing mail account. You would need to make sure the Account Settings have it set up to 'leave messages on server'. Pop accounts can only access the server 'Inbox', so if you have emails in a server 'Archives' folder, you would need to logon to webmail and manually move all those emails into the server Inbox and then in Thunderbird click on 'Get Messages' to download them.

Then in webmail, move all those emails in Inbox back into the 'Archives' folder.

Then swap back server setting to imap.

re :Does that include Archives? They are not stored on my computer?

Do you mean 'Archives' folder is a folder on the server containing emails? Can you see that 'Archives' folder in the Thunderbird imap account? If no, you need to 'Subscribe' to see that server 'Archives' folder. Right click on imap mail account name and select 'Subscribe' You need to select the 'Archives' folder and any of it's subfolders and click on 'Subscribe'. Click on OK.

If yes, you can see 'Archives' folder in the imap account, it contains emails and you would like to download full copies and then get copies into 'Local Folders' mail account.

• Right click on imap mail account name in Folder Pane and select 'Settings'
• Select 'Synchronisation & Storage'
• click on 'Advanced..' button
• Make sure the 'Archives' folder and all of it's subfolders have their respective checkboxes selected.
• click on OK
• click on OK

• Menu icon > File > Offline > Download/sync now
• Select checkbox 'Mail messages'
• select checkbox 'Work offline once download and/or synchronisation is complete.'
• click on OK

Folders get synchronised. Thunderbird will go into offline mode. In bottom far left status bar, you will see the 'two blue screen' icon turn into a 'two black screen' icon when offline.

Test: Can you select and read the contents of a few randonly selected emails that are in the Archives folder? If yes, all is good, you have full copies.

Create some suitably named folders in 'Local Folders' mail account. Highlight batches of emails that are in the imap Archives folder. Right click on highlighted emails and select 'Copy to' and choose suitable folder in 'Local Folders' mail account. Repeat until all emails copied over. Spot check on a some random emails - can you read those copied emails? If yes, all is good.

When finished you can go back to online mode by clicking on that 'two black screen' icon.

Once all emails are copied to where you want them. I would suggest you perform a backup.

Exit Thunderbird and access your Profile folders. Profile located here: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird Copy the 'Thunderbird' folder to an external device/hardrive.

That's work great, I did it as IMAP as you said. I have no archives but I could see the folder so I subscribed to all folders and archived my inbox, copied it back to the my inbox and the local folders inbox and I can read them from there. I just need to save the profile, when I need to free up space on the server and I remove emails they will not be removed from the next profile & back-up if they are in the local folders. Is correct is it? Thanks you couldn't have been more clear straight forward!