GPGMail cannot decrypt some messages previously sent/received, decryption via CLI works with warning "gpg: WARNING: message was not integrity protected"

gpg_dude's Avatar


12 Jun, 2018 01:27 AM

I have some messages from a few months ago that were sent/received to/from a particular person that I am now unable to decrypt natively in Apple Mail using the latest GPGTools/GPGMail production build 2018.2. I don't get any error, but I also don't get a decrypted message - just 2 raw attachments show (Mime Attachment & encrypted.asc). I saved encrypted.asc and used gpg on the CLI to decrypt it manually and it succeeded, but displayed this error: "gpg: WARNING: message was not integrity protected". It seems all messages I sent to or received from this person in the past have this issue and I'm not sure why. Any ideas?

  1. Support Staff 1 Posted by Steve on 23 Jun, 2018 12:38 PM

    Steve's Avatar

    Hi gpg_dude,

    please take the time to thoroughly read the Modification Detection Code (MDC) Errors KB. It explains what the integrity check does and why it is important to be used.

    As for the why it is happening only with this specific recipient, chances are that they are using an old OpenPGP key with weak security. Transitioning to a stronger key may resolve the problem.


Reply to this discussion

Internal reply

Formatting help / Preview (switch to plain text) No formatting (switch to Markdown)

Attaching KB article:


Attached Files

You can attach files up to 10MB

If you don't have an account yet, we need to confirm you're human and not a machine trying to post spam.

Keyboard shortcuts


? Show this help
ESC Blurs the current field

Comment Form

r Focus the comment reply box
^ + ↩ Submit the comment

You can use Command ⌘ instead of Control ^ on Mac