I posted about this issue months ago. I got a reply but it didn't fully solve my problem. 1. I had this email account set up on a device, working perfectly fine. It was an using an IMAP protocol. No issues. 2. I needed to add this account to a new device, (at my home, away from work). 3. When I signed into the account, it setup the email using POP3 instead of IMAP. Ever since this has been setup, the email at the workplace (using IMAP) was missing thousands of emails from the inbox. Only the inbox, no other folders were affected. The device at the home (POP3) retains all those previous emails in the inbox but is missing many emails from the SENT folder. Nothing was deleted. There is nothing in junk. This change with the POP3 protocol is the only factor that could explain why this has screwed up our past year. When I access the webmail, none of those emails from the inbox are there. I attempted to copy the profile from the POP3 computer at home and pasted it into a new thunderbird configuration at the workplace. No accounts were there when I pasted the profile. However, this has only acted as a storage unit for the emails and is not a functioning account. Does anyone have advice on how to rectify this without losing the old emails?