Uninstalling Universal Type Client for Windows
To uninstall Universal Type Client for Windows, go to Settings > Apps, select Universal Type Client, and click Uninstall. Windows will ask you to confirm that you want to uninstall; click Uninstall.
Once UTC has been removed, go to C:\Users\username\AppData\Local\ and drag the Extensis folder to the Trash.
Uninstalling Universal Type Client for Mac
Download the Universal Type Client uninstaller script from https://cs.extensis.com/font/uts/uninstall-utc.zip. Double-click to launch the script and follow the instructions that appear.
You may get a warning that macOS can't verify that the script is free from malware.
Control-click on the uninstall-utc.command file and select the Open option from the dropdown menu; you will get a different dialog with two buttons. Click Open.