This is pretty funny. I don’t know how it happened nor why this can solve it. All I know is this will work out somehow.
Brief descriptions: POP did not download e-mails from Gmail account before a specific date.
Symptoms: I set up POP in Thunderbird and download e-mails from Gmail account. All went well except that e-mails arrived before 8/26/06 were not downloaded to my computer. No matter what I did the emails wouldn’t get downloaded. So I revisited the setting in the Gmail account >mail setting>Forwarding and POP/IMAP>POP Download and I found that it showed “POP is enabled for all mail that has arrived since 8/26/06” which corresponding exactly with the not-downloaded emails in the gmail account. However, I don’t know how to change the date. I ticked at “Enable POP for all mail (even mail that’s already been downloaded)” and saved the changes, but that did not help.
Here is the trickery…I don’t know how or why though. I ticked on “Enable POP for mail that arrives from now on” then save the changes. After that I ticked “Enable POP for all mail (even mail that’s already been downloaded)” then save the changes. Now it works!
Here they discussed the same problems too
If your Gmail is full and you think you need to store all your old e-mails to your computer, you may consider using Thunderbird. But you might encounter some problems when using it. Here I collected some links regarding the problems and solutions.
Gmail: Move all emails in trash to inbox
How to Uninstall Thunderbird Completely and Then Reinstall It
“Thunderbird is already running, but is not responding. To open a new window, you must first close the existing Thunderbird process, or restart your system.”