I moved to a different cloud server for website and email service - seem to lose past emails

I seem to lose the already received emails when I move a domain and email service from Rackspace/liquidHosting to TMD Cloud.  So I change the nameservers address on my domain name and set up domain and email service with exact same email address on the new TMD Cloud service. Then on using emclient to download new emails, the emails previously downloaded disappear and I start with a welcome message from the email server at TMD. I don’t understand why emClient is deleting the emails?  Is there a difference between POP and IMAP that might cause this?

Basically POP3 stores the messages on the computer, so if you remove the account from eM Client, you delete all the data. IMAP stores them on the server, so if your server account is deleted, so is the data. 

But you can restore from your most recent backup. You may lose a few messages, but most should be there depending on how recent the backup was. If you want to try the restore, disconnect from the Internet before you begin. Once the restore is complete, move the messages from IMAP or POP3 folders to Local Folders before reconnecting to the Internet. Then remove the old account, and add the new. Once that has connected, you can then move the message from Local Folders to the new account folders.

NOTE:  If you were using IMAP, but eM Client was not configured to download messages for offline use, including attachments, then the backup will not be of any use, as it will only contain the message headers, but not the message content. 

The best practice when you are about to move the account from one server to another is to copy the messages from the IMAP or POP3 folders to Local Folders, or export them to .eml files. Then once the new server is setup, and you have added the account to eM Client, you can move the messages to those folders. I guess that is not very useful in hindsight.

Thanks for the quick reply Gary!  I’ll follow your advice