Email client for Linux which can store GPG messages decrypted

While I never used a GUI email client which does that, you can use mutt [ which is a CLI email client ], and which has two useful commands:

• decrypt-copy -> Lets you save the decrypted contents of an email to a file
• decrypt-save -> Does a decrypt-copy then deletes the email

These two commands are unbound by default, but you can bind them with the bind command, e.g.:

bind pager <F5> decrypt-copy
bind pager <F6> decrypt-save

Would make F5 do a decrypt-copy and F6 do a decrypt-save

KMail supposedly has a setting for this. However, the documentation is ambiguous as to whether it actually works:

Symptom: You exchange encrypted mail with a friend, but would like to store it unencrypted, once you have opened the message.

Solution: To store emails that have been decrypted once in unencrypted format henceforth, add this to your kmailrc configuration file, in the [Reader] section:

store-displayed-messages-unencrypted=true

This may only work with SMIME but implementation for OpenPgP is being worked on.