Application Availability, Architecture, and User Implementation Date: October 2023 Status: Verified Overview

Proton has successfully delivered on its promise to bring encrypted email out of the browser and onto the desktop. If you’re already paying for Proton, downloading the Windows app is a no-brainer. For free users, it’s yet another reason to consider upgrading.

High CPU usage during sync. Fix: This usually happens on first sync of a large mailbox (over 20,000 emails). Let it complete; subsequent syncs are incremental and lightweight.