
Re: That was an S/MIME issue...
Every other PGP/GPG-encrypted message I've ever received marked the encrypted portion with the content-type 'application/pgp-encrypted', and the signature 'application/pgp-signature'.
\r\n\r\n
Yours appears to have done neither. Perhaps some clients sniff for the 'BEGIN PGP MESSAGE' line, and Evolution doesn't?
\r\n\r\n
Saving the message and decrypting on the command line worked OK.