Avoid external monitor go to sleep

ugaciaka,

Thanks for reaching back out. Depending on the type of monitor you have, there may be a built-in sleep timer. We'd recommend checking with the manufacturer to see if they're able to lend any support to accomplish what you're looking for.

The following user guide offers available sleep and wake settings on your Mac notebook: Set sleep and wake settings for your Mac

Take care!

Hi ugaciaka,

Thanks for taking the time to post your question to Apple Support Communities! Based on your post, it sounds like you have question about your external monitor going to sleep when closing the built-in display of your MacBook Air. We're happy to provide some information.

Check out the "Connect your display" section of Connect a display to your Mac

As mentioned, "If you use an external keyboard and mouse with your Mac notebook, you can close the built-in display after you connect your external display. You might have to press a key or click your mouse to wake the external display."

To confirm, does the external monitor wake after clicking or pressing a key on your external mouse or keyboard? This information will help us determine whether the behavior you're experiencing is expected.

Regards.