Loads of previously read emails suddenly appearing

[#1]

Hey, I just raised a ticket for this. There's some weirdness going on with my email account.
Ticket text:
- - - - - - -
Suddenly about 1000 GMT I have had over 1000 old emails, previouly marked read, downloaded to my mailbox (some account)@plus.com.
What is going on?
Am I the only one?
- - - - - - -
Pete
Edited my email address out...

[#2]

Do you have your email client set to leave a copy of emails on the server? If so it's almost certain that the problem is it has forgotten which ones it has already downloaded.
If you are leaving emails on the server so that you can see them in webmail you would do far better to use IMAP instead of POP3 in your mail client.

[#3]

Are you using a Microsoft-engineered email client? If so, it could be a problem with your popuidl.dbx file. This keeps track of the emails you have already downloaded.