ScreenDiag
ScreenDiag is a macOS display testing app for checking monitor quality, color behavior, sharpness, motion, HDR, and viewing characteristics.
What is ScreenDiag?
ScreenDiag is a native macOS utility for evaluating the quality and behavior of connected displays. It helps users inspect common monitor issues such as dead or stuck pixels, backlight problems, banding, sharpness, scaling, motion artifacts, and color consistency. The app includes dedicated test groups for solid colors, gradients, geometry and sharpness patterns, response performance, HDR, color accuracy, and viewing angles, along with technical display information for each connected screen. This makes it useful for photographers, designers, gamers, IT staff, and anyone assessing a new monitor or troubleshooting display quality. ScreenDiag is published by Utap and is designed for fullscreen testing workflows on modern versions of macOS.
Key features
- View technical details for connected displays, including resolution, refresh rate, scale factor, and pixel density
- Run solid color tests to spot dead pixels, stuck pixels, backlight bleeding, and uniformity issues
- Check gradients and grayscale patterns for banding, gamma issues, and uneven color transitions
- Use grid, checkerboard, alignment, and sharpness patterns to evaluate geometry and pixel accuracy
- Test motion behavior for refresh performance, blur, ghosting, and frame stability
- Assess HDR behavior, highlight clipping, dark detail, and contrast handling
- Review color-focused patterns for white balance, channel balance, and reference tones
- Examine viewing angle behavior, brightness falloff, and off-axis color shift
Review app leftovers with diCleaner
Inspect caches, support files, containers, and login items before cleaning.
Safety overview
Status: Mostly safe
This app performs on-screen display tests and reads information about connected monitors, which is normal for its purpose. It does not need unusual system-level privileges to show test patterns, but users should still install it from a trusted source and only grant permissions that make sense for the features they use. Removing it simply takes away its display testing tools and should not affect normal macOS display operation.
Recommendation: Keep ScreenDiag if you use it to evaluate monitor quality, compare displays, or troubleshoot image issues. If you no longer test screens or check display behavior, you can remove it without affecting everyday use of your Mac beyond losing these diagnostics.
Common paths
/Applications/ScreenDiag.app
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