Why do I keep receiving emails that I have received weeks ago?

Question

About once a week I will receive 2-3 emails that I had received weeks ago. They appear as new emails and are not sent again by the original sender. The duplicated emails seem quite random.

Answer 1

It is possible that your popstate.dat file may have incorrect info for that email or some other corruption has caused it to go awol.
See info here:
http://kb.mozillazine.org/Popstate.dat
You could delete the popstate.dat file and it will create a new one.
The downside is that anything on the server will be downloaded again, but only once.
'''How to access popstate.dat file.'''
make hidden files and folders visible:
* http://kb.mozillazine.org/Show_hidden_files_and_folders
You can also navigate directly to your profile folder at the following path:
The AppData folder is folder is a hidden folder; to show hidden folders, open a Windows Explorer window and choose "Organize → Folder and Search Options → Folder Options → View (tab) → Show hidden files and folders".
C:\Users\Windows user name\AppData\Roaming\Thunderbird\Profiles\Profile name\ Mail\mail account name
Easy way to access via Thunderbird after making hidden files visible.
* Help > Troubleshooting Information
* click on 'show folder' button
a new window opens showing your Profile folder.
*''' Close thunderbird now - this is important.'''
* click on 'Mail' folder
* click on mail account name
* look for 'popstate.dat' file and delete it.
* Close window.
* Retart Thunderbird.