Unable to download large messages in Thunderbird
Follow the instructions to download large messages in Thunderbird:
From the ‘Tools’ menu, click ‘Account Settings’.
From the left pane, under the e-mail account, click ‘Disk Space’.
Clear the ‘Messages larger than’ check box.
Thunderbird enables you to set up an e-mail account, compose and send e-mails, attach files with e-mail, or import contacts and address books. At times, you are unable to download incoming e-mail messages with large size. You need to change the account settings to resolve the problem from the ‘Account Settings’ and clear the ‘Messages larger than’ check box.