My Thunderbird is running with just the default profile as shown in Profile Manager when Thunderbird is called up with -p switch. Thunderbird accesses 3 email accounts on 3 different servers, i.e. there are 3 accounts each with an individual email address, inbox, sent mail and many other folders. One of the email accounts (Comca$t, wouldn't you know it!!) ceased to receive emails recently. After lengthy investigation and very sluggish help from Comcast I finally learned that Comcast had changed email server protocol from POP to IMAP (without notification to me). There is no issue with other two accounts. Then I learned that it's not as simple as modifying existing Thunderbird program to change the Comcast email account to IMAP. Thunderbird must be reinstalled. If I save the default profile to a folder then reinstall Thunderbird how do I populate the three accounts in Thunderbird with all of the files that were in the three accounts in my original Thunderbird program? Do I need to disable or delete the old Thunderbird program before installing the new program? Do I have to know passwords and account settings for all accounts to respond to Thunderbird queries during installation or does that happen automatically? It is profoundly, absolutely essential that I not lose a single file from any of the 3 accounts in this process and that the email account that will now become an IMAP account have the same email address as it always had before Comcast changed its email server protocol. Thanks, Barry H.