This article is for Cable Matters model numbers 201018 / 201028 / 201031 / 201062 / 201038 / 201088 to solve the refresh rate issue in macOS after updating to 10.14 Mojave. In the new macOS, the refresh rate list box has been removed for HDMI adapters.
Mojave Previous macOS
Since macOS defaults to 30Hz and now does not allow users to manually change to 60Hz, it is inconvenient for users who need 60Hz while using Cable Matters USB-C adapters and cables. We found a safe and convenient utility tool called Retina Display Menu (RDM) which can adjust the refresh rate with just a couple of clicks. Please follow the steps below to download and install the utility.
1. Download and unzip the utility
2. Install the utility
3. If you see the error message below, you need to grant access to the installation program.
4. Go to System Preferences -> Security & Privacy
5. Click the lock icon on the bottom left and enter the system password. Then click 'Open Anyway' next to the block list where RDM shows up.
6. Follow the installation steps to finish installation. In the Launchpad you will then find the RDM app.
7. Click on the App and an icon will appear in the icon bar. Click it to select 60Hz in the drop down menu.