Browse by Topic: Problem Solving
Resolving Thunderbird/Enigmail decryption errors for encrypted emails with large attachments
Last modified on 20 February 2020 11:58 AM

The Thunderbird email client, using the Enigmail plugin, may fail to decrypt and open emails with attachments above 20mb or so in size. Typically, the email fails to open, and errors along the lines of "Decryption incomplete; click Key icon" and "Error - IMAP message too large to decrypt/verify" are shown.

The issue lies in Thunderbird's handling of mail attachments. To work around this issue, please do the following:

  1. Select Enigmail 
  2. Click Preferences 
  3. Click Advanced from the Thunderbird menu bar
  4. Make sure the option Only download attachments when opened (IMAP only) is unchecked.

More information on how to add StartMail to the Thunderbird email client can be found here.


(15 vote(s))
This article was helpful
This article was not helpful

Still haven't found the answer to your question? Click here to contact support.