Even with a portable app, it's a good habit to log out if you are using a high-risk public computer.
The official Proton Mail desktop app is built on Electron. While the installer defaults to a local directory, you can often "portabilize" it manually. How to do it:
Proton Mail Desktop App Portable: Your Secure Inbox on the Go proton mail desktop app portable
Because the browser itself is portable, all your session data and the "app" interface stay within the portable browser's folder on your USB drive. Security Best Practices for Portable Users
Once the Bridge is running, Thunderbird will see your Proton account as a local account. Even with a portable app, it's a good
In an era of increasing digital surveillance and data breaches, Proton Mail has emerged as the gold standard for encrypted communication. While many users rely on the web interface or mobile apps, power users often seek a version.
Use a tool like 7-Zip to open the Proton Mail .exe installer. How to do it: Proton Mail Desktop App
If you lose your thumb drive, anyone can access your local cache. Use a hardware-encrypted drive or a tool like VeraCrypt to protect the partition.
By default, Electron apps still save user data (your login session and cache) in the %AppData% folder of the host PC. To make it truly portable, you would need to use a command-line flag like --user-data-dir=".\data" to force the app to save information to the USB drive instead of the computer. Option 2: Using the Proton Mail Bridge (Portable Mode)
(Note: The Bridge itself isn't officially portable, but you can copy the installed program files to a USB).