If you desperately need a portable encrypted email client, consider switching to (which has a somewhat better offline portable experience) or using Mailpile (an open-source email client designed for USB sticks).
Uses Proton’s full web interface; perfectly secure; no third-party software. Cons: Slower than a native app; consumes more RAM. proton mail desktop app portable
For users who need offline access and full desktop functionality, combine with a portable email client like Thunderbird Portable. If you desperately need a portable encrypted email
achieves 90% of what people want from a portable app. For users who need offline access and full
Currently, there is no official "portable" version of the Proton Mail desktop app designed to run from a USB drive without installation. Proton's official desktop application requires installation on , macOS 10.15+ , or Linux and is primarily available to users with a paid plan (though free users can access a 14-day trial).
So, does a exist? Not officially. But with third-party tools like ElectronMail or a self-contained Chromium profile, you can achieve 90% of the portability dream.