Disable an External Monitor?

Question

Level 1

145 points

Disable an External Monitor?

I am looking for a way to disable a second monitor (plugged into the Display Port of a late 2010 iMac 27") without unplugging it. Does anyone know of a software solution?

When I am working I like that second monitor for desktop space, but other times (watching Netflix for example) the second monitor taxes the video card to much and degrades video playback performance. It would be great to have a software switch to ignore the second monitor. Right now, the only way I have found to do this is to unplug the display port cable.

Posted on Jul 17, 2011 9:34 AM

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Answer 1

m0thr4

Level 2

298 points

Jul 7, 2017 2:37 AM in response to Tracy E

Well, it didn't do what I was expecting. I assumed that "disabling" the external monitor would cut off the input, thereby allowing me to switch the input on the external monitor to another device while ensuring the iMac is working to just one screen.

Unfortunately, what I found is that the iMac screen goes blank and the external monitor retains its picture, but is disabled. This leaves me with an iMac that I cannot use until I physically unplug the external monitor.

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Answer 2

m0thr4

Level 2

298 points

Jul 7, 2017 2:39 AM in response to Radwan Kakar

This is fine unless you want to use the external monitor for something else. My external monitor has several switchable inputs, so I can plug in a games console, or laptop.

Unfortunately, the only workable solution I've found is to unplug it from the iMac when I don't want it to be a secondary monitor to that.

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Answer 3

captfred

Level 7

26,422 points

Jul 17, 2011 9:37 AM in response to Tracy E

Best to just turn the second monitor off with the power switch.

Regards,

Captfred

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Answer 4

Tracy E Author

Level 1

145 points

Jul 17, 2011 9:40 AM in response to captfred

Power switch turns off monitor, but does not disable it from appearing active to the iMac (at least on my system). Should it? It is attached with a DVI cable to a display port adapter.

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Answer 5

captfred

Level 7

26,422 points

Jul 17, 2011 9:47 AM in response to Tracy E

Interesting, same behavior with mine. Although it still appears in system preferences, it knows it's not present as my menubar switches to the other screen.

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Answer 6

Tracy E Author

Level 1

145 points

Jul 17, 2011 12:37 PM in response to captfred

I tried your test and got different results. My system did not become aware of the change at all like yours.

I put the menu bar on the 2nd monitor and turned it off, but the system did not switch to the other screen.

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Answer 7

X423424X

Level 6

14,265 points

Jul 17, 2011 12:37 PM in response to Tracy E

SwitchResX is precisely made for this. Indeed it is the only OS X software I've seen made for just these kind of problems. I use it to enable/disable my TV when I want to watch movies. I highly recommend it.

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Answer 8

Tracy E Author

Level 1

145 points

Jul 17, 2011 1:11 PM in response to X423424X

Yes! Funny, I just found it and was coming back to the forum to post about it. It works well. It costs $19 USD, and seems well worth it.

You can easily make Display Sets – predetermined configurations for monitor activation, resolution, etc. I quickly whipped up this menu to control all my monitors.

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Answer 9

X423424X

Level 6

14,265 points

Jul 17, 2011 1:59 PM in response to Tracy E

Yes, and if you notice in that picture, that SwitchResX has a provision to execute an applescript along with the switching. I took advantage of that to allow me to move my audio between my mac and tv and also change the cursor size (hard to see that little bugger on the tv 7 feet away unless you make it bigger).

It also allows you to move the menu bar (see main display) which I needed in a display set to move on to the tv since one site I use only supports full screen display on the screen containing the menu bar.

All-in-all a very nice utility.

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Answer 10

Mar 25, 2013 10:22 AM in response to X423424X

Searching for a lot of time.. very nice !!! Thanks

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Answer 11

Sep 14, 2016 9:41 AM in response to Tracy E

Well, There is one thing that helped me was mirroring the display and switching of the monitor. So mouse cursor will stay in the screen. This can achieved by going to:

System Preference->Displays->Arrangements and chick the mirror display box.

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