License Verification

From YoYoGames Wiki

Game Maker requires re-authentication at least once a month. This means requires an internet connection. Alternatively, the file can be manually downloaded and Game Maker can be configured to recognize it. To do this, when prompted to provide a new License check file, go to the Help menu and select License Verification File. A file dialog will then appear. Navigate to the location of the file, and select it. Game Maker must be restarted to complete the verification process.

If you need to do this manually, the file can be downloaded here