Backing up Windows Mail on Windows 10

[poit57]

My parents moved outside of the service area of the ISP that we've had since I was a teenager, and I now have an account of my own through the same ISP. We plan on transferring the email addresses to my own account, but my brother has been using the Mail app in Windows 8 and now Windows 10 to access email as IMAP since 2013. The rest of the family has email saved using Outlook .pst files (configured the email as POP3)

It doesn't appear that there is any backup or export feature from the Mail app. On the ISP's mail server, my brother currently has almost 1200 messages dating back to 2013. Will he lose what's previously been synced with his computer, or will all the old emails in the Mail app disappear when the ISP email address is deleted and recreated on a difference service account?

If messages will be deleted, are there any suggestions for archiving past messages incase they're needed in the future? I could save them to a .pst file using Outlook on my computer, but my brother wouldn't be able to access them without having Outlook on his own computer.

 

[realwarder]

Given that you have Outlook, cheapest way is to export to PST from his current account. Then add his new one and load them back in there from the PST.

If he signs up and uses Outlook.com (free email service) then you can actually Import all email from another IMAP account into your new account there as a feature of that service. Just go into the options.

 

[poit57]

I was looking at my brother's Outlook.com account. He apparently had previously connected the ISP account (About 16,000 messages dating back to 2011), but there was an error in the connection so that the most recent message showing up in the Outlook.com inbox was from last November.

I deleted and reconnected his ISP account as IMAP through Oultook.com, and it appears to now be fully up to date with all past messages. I'm assuming there is some built-in cleanup feature. Prior to 2016, he was syncing his ISP email with Outlook.com as POP3, and then synced all remaining messages from 2013 to present as IMAP as of yesterday. I didn't see any duplicated messages between 2013 and 2016 after Outlook.com was finished syncing with the ISP email.