Exchange - Use Temporary Mailbox or Use Old Data

[PB4cyber]

See image of error message.

What does this mean specifically?

• Are there now 2 accounts (sets of data) on the Exchange server? Or 2 sets locally? 
• Can this message appear with pop3/IMAP email accounts OR ONLY with office 365 account?
• Why would my mailbox move? All I did was upgrade from Office 365 Essential to Office 365 Business Premium.
• Does this mean I have to go check between both 1) Temporary Mailbox and 2) Old Data which one has the correct data and copy from one to the other?
• Once data is verified, how do I set the Mailbox to be the only one used? The message Temporary Mailbox and Old data seem they are both problematic and not the final solution. 

Thanks

[JesseW]

Hi @PB4cyber. Welcome to GoDaddy Community! In researching the issue, I was able to find this Microsoft support article. I think it will help your situation.  Hope you're able to get it worked out!