Heads-up for Mac users: after updating to macOS 27, the checkboxes in MKVToolNix GUI are invisible. You can still check and uncheck each row but without visual confirmation. I can reproduce it on macOS 27 with MKVToolNix versions 99 through 102. Thanks to Guilouz who reported the issue to me on GitHub.
It doesn’t look specific to MKVToolNix. qBittorrent users are seeing the same thing on macOS 27 ( Select box is invisible after updating to MacOS 27 · Issue #24921 · qbittorrent/qBittorrent · GitHub ), so it appears to be Qt’s native macOS style not getting along with macOS 27.
The workaround is to launch with Qt’s built-in Fusion style, which draws its own controls instead of using the macOS ones. The GUI looks a bit less Mac-like, but the checkboxes are back. Quit MKVToolNix, then use either method:
Terminal: run this command.
open "/Applications/MKVToolNix.app" --args -style fusion
Double-click app: open Script Editor, paste this line, and save it with File Format set to Application.
do shell script "open '/Applications/MKVToolNix.app' --args -style fusion"
Notes:
- If you use the Terminal method, you can close Terminal right away and MKVToolNix keeps running.
- The fix only applies when you launch MKVToolNix one of these ways. Opening it from the Dock or Finder goes back to the default style.
- If your app is named differently (for example
MKVToolNix-102.0.app) or isn’t in/Applications, change the path in whichever method you use.