Due to an error that occurred when rolling out a new version of our IMAP server software yesterday, some users may have experienced new emails arriving in folders appearing as completely "blank". These emails would have an empty subject, empty from address and empty/invalid date.
The problem that caused this was not damaging the emails in any way, it was just returning the wrong data back to the email software, and was only present for about 30 minutes. The problem has been fixed, but some email clients (eg Outlook Express, Thunderbird, etc) may continue to cache the old "bad" information on emails that were downloaded during that time.
In most cases, the solution is to just clear the local folder cache, causing the email software to re-download the message list. You can do that by: