A new open-source app called CornerFix restores the sharp display edges Apple removed in macOS 26 (Tahoe). Developed by Mehmet T. AKALIN, it's a lightweight Swift menu bar utility that draws customizable, click-through overlay caps to visually square the screen's silhouette. It's designed to be safe, SIP-friendly, and doesn't alter individual app windows.

The tool addresses a design change many users find distracting, as macOS 26 introduced more aggressively rounded corners with no system setting to disable them. CornerFix provides a non-invasive workaround, supporting multi-monitor setups and offering adjustable cap sizes and colors. It’s built for SwiftUI and requires Xcode 15+ on macOS 13+.

For developers, the project serves as a practical example of working with Swift window overlays and system UI customization. Its MIT-licensed code is available on GitHub, inviting contributions and forks. The app's existence highlights a niche but passionate user base seeking to reclaim pixel-perfect control over their Mac desktop experience.