How to Detect Displays on a Mac with OS X Mavericks

Mar 31, 2014 - 9 Comments

Detect Displays in Mac OS X

Typically when an external display is connected to a Mac, it will automatically be detected and start working instantly, with the Mac either extending the desktop or mirroring the screen over to the newly attached display output. Sometimes that doesn’t happen however, and when a secondary screen is not detected automatically by the Mac, you’ll want to trigger the “Detect Display” function in OS X.

Like some other features in new versions of OS X, the “Detect Displays” button is now hidden by default, no longer immediately visible in the Display Preferences of Mavericks. This does not indicate a problem with the Mac or with the external screen you wish to use, you simply have to toggle the Option key to make the detect feature visible and then be able to run the detection as usual. This applies to secondary displays of all types, whether it’s an external monitor, AirPlay mirroring, AirDisplay, a projector, an HDMI connection to a TV, or whatever other additional screen you have attempted to connect to the Mac. If you’re having any issues either showing the feature or getting an external screen to show up properly, this is what you’ll want to do.

Use Detect Displays for External Screens on a Mac in OS X Mavericks

With the secondary display to detect already connected to the Mac, do the following:

  1. Go to the  Apple menu and choose System Preferences
  2. Choose the “Displays” panel
  3. Hold down the “Option” key to show the “Detect Displays” button – note that it replaces the ‘Gather Windows’ button
  4. Click on “Detect Displays” while holding down Option to use the function as intended

Show Detect Displays in Mac Displays panel

At this point the external screen should be found and work as usual, launching the secondary “Displays” window for that screen. Of course you’ll want to be sure the physical connection is secured for the external display, and if you’re having any issues check the cables to the LCD monitor, projector, or TV.

It should be pointed out that having the “Detect Displays” button not being visible in OS X Mavericks is not an indicator of a problem or a bug, and it’s certainly not indicative of an issue with the output device, it’s simply hidden from casual use, presumably because most of the time the Mac usually has no issues finding and connecting to external screens. Nonetheless, sometimes you have to forcibly detect an external display, which is why this feature is a little curious to hide by default.

Using the “detect” feature should be the first troubleshooting step taken if you can’t find a video output device that is connected to a Mac, though more advanced methods may need to be taken if there are other issues, such as flickering or noisy displays, which may require an SMC reset to resolve.

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Posted by: Paul Horowitz in Mac OS X, Tips & Tricks


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  1. R Tucker says:

    Is there a way to make the [detect displays] button show by default? I use this quite a bit connecting to various displays for presentations.
    Thanks. RT

  2. LensKaraoke says:

    I do this all the time in my job but with the new Mavericks I get the menu bar across the top on the external screen. Is there a way to get rid of this

  3. CD says:

    This is such a good tip. Before I read this tip, I would have to restart my MacBook in order to get it to detect my external monitor. Thank you!

  4. Michael says:

    Is this another ‘improvement’ by the iOS team? Yes, the mac should detect the display (or projector) automatically, but it usually doesn’t if the device was made by Dell.

  5. L_MO says:

    Using the option button does display the hidden display button but nothing happens when I click it. Macbook still does not connect to Sony Bravia. Any other suggestions?

  6. LO says:

    I’ve had trouble with this for years. Genius tip – thank you!!!!!!!

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