Mail store migration can corrupt timestamps on emails

The mtime (modification time) must be preserved when copying emails. If the mailstore is moved and timestamps on the files are not preserved, then the new mailstore will cause IMAP clients and webmail to show the mail dates wrongly.

If you are running OSX or Linux, then you can use the following script to fix the timestamps. The script reads the bodies of the emails, converts the dates to a timestamp, and updates the times on the files so they will appear correctly.

The script.