On a Mac, go to System Preferences > Security & Privacy > Privacy > Screen Recording and make sure your Browser is listed, and selected.
If you are experiencing problems sharing your screen in your browser, make sure you have enabled your security settings for screen recording. Google Hangouts screen sharing not working? Solve the issue Screen sharing stops as soon as the call is disconnected. Depending on your network speed, the process may take a little while but once you are connected, all video participants will be able to view your screen and all actions you undertake on your computer including keyboard and mouse actions. To finish the process, click “Present to everyone”.Simply select the window you wish to share to continue. If you select the “Window” option, you will be presented with all the current windows that are open on your machine.Select either “Entire Screen” or “Window” from the options available and click “Share”.If you are using a mobile application use the meatballs menu option (three dots) to open additional options. Start a video call and select the “Share Screen” option from the top right menu options.Launch Google Hangouts on your desktop or app.The process might vary slightly depending on whether you’re using Hangouts in your browser or as a mobile application.