OS X El Capitan: Set screen sharing preferences

Start a screen sharing session with a Mac on your network. See Share the screen of another Mac.

Choose Screen Sharing > Preferences, then set the following options:

• Under Display, select “Scale to fit available space” or “Show full size,” depending on how large your screen is and how much of it you want to use for the shared screen. This option changes the default behavior for when you share the screens of computers you’ve never connected to before. To change the current scale, choose View > Turn Scaling Off or View > Turn Scaling On.

• Under Display, select a “Scroll the screen” option to determine how the screen sharing window behaves when you move the pointer. To decide which option you want, try each one by selecting it, then moving the pointer around in the window.

• Under Quality, select “Adapt quality to network conditions” to view the shared screen more quickly, or “Show the screen at full quality” for a more detailed view of the shared screen. This option changes the default behavior for when you share the screens of computers you’ve never connected to before. To change the current scale, choose View > Adaptive Quality or View > Full Quality.

  For the best results, and if your Mac is connected to a fast network, view the screen at full size and show the screen at full quality.

• Under Blocked Users, choose an option from the “Allow screen sharing requests from” pop-up menu to enable sharing your screen with either everyone who tries to connect to your computer using an Apple ID or just your contacts.

  To block users with specific Apple IDs from sharing your screen, click the Add button , enter the user’s Apple ID, then click Block. To unblock users, select them in the list and click the Remove button .