[bitL]

Anyone knows how to use Protonmail to send/receive attachments encrypted by a different PGP key than Protonmail uses for one's account? It never allows to download such an attachment and I surely won't upload my private key there...

[vabmit]

Please report your difficulties to the Support Team: https://protonmail.com/support-form You don't need to be a paid user to do this. They will respond to your ticket. I have done this before - some time ago. But, perhaps a bug was introduced somewhere in the code or there is some other issue that you are running into (perhaps some configuration with the local platform). It should be possible and work correctly.