When macOS 26 Tahoe arrived last month, many users noticed their Macs running hotter and slower than before. The problem wasn’t with Apple’s new system itself but with several popular Electron-based apps that suddenly began drawing excessive GPU power. This slowdown caught the attention of both developers and users who rely on apps like Discord, Slack, and Figma for daily work.
Likely cause behind the slowdown
Electron, the framework powering many cross-platform desktop apps, had been using a private Apple API called cornerMask (via 9to5mac). Private APIs often exist for Apple’s internal use, not for third-party developers. According to Electron’s own changelog, this particular API stopped working correctly after the Tahoe update, triggering massive GPU spikes and performance drops across systems. Users reported that their MacBooks overheated and fans spun constantly, even when idle.
Developers behind the Electron project acted quickly once the issue surfaced. They removed the problematic API from newer versions of the framework, restoring normal GPU behavior. Apple did not publicly acknowledge the change that broke compatibility, but the fix confirmed what many suspected: the slowdown came from how Electron apps interacted with macOS Tahoe’s updated graphics layer.
Which Apps Have Been Updated
As reported through the open tracker ShameElectron, several major apps have already implemented the fixed Electron version. These include Claude, Discord, Docker Desktop, Figma, GitHub Desktop, Notion, Obsidian, Pocket Casts, Signal, Slack, and Visual Studio Code. Each of these now runs more efficiently under macOS Tahoe, showing normal GPU load and temperature levels again.
However, not every app has caught up. Tools like 1Password, Bitwarden, Cursor, Dropbox, and Windsurf still use the outdated Electron version. Until their developers push the update, users may continue seeing reduced performance and higher battery drain. The tracker remains the easiest way to check which apps have received the fix and which have not.
What Users Should Do
If your Mac feels unusually warm or laggy after upgrading to macOS Tahoe, check your running Electron apps. Updating them to the latest version often resolves the slowdown immediately. You can also quit unused apps or temporarily switch to their web counterparts. Developers are actively rolling out patches, so the situation should continue to improve in the coming days.
The macOS Tahoe slowdown became a reminder of how fragile private API dependencies can be. Apple’s changes may appear minor internally, but they ripple across countless third-party tools. Fortunately, this time developers acted fast, and your Mac should soon feel as smooth as before.
