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I frequently use Remote Desktop to access my home iMac from my university campus (using a 13" MacBook with resolution 1280x800). The iMac has two displays, the built in 27" 2560x1440 display and an external 1920x1080 display. There are three issues:

  1. Scaling down the resolution makes everything small, or I have to do awkward/annoying panning. I typically only view the 1920x1080 display over Remote Desktop, but even then it's sub-optimal.
  2. Large displays require high bandwidth. This isn't an issue if I'm at a proper WiFi network such as my university campus, but occasionally I also use my phone's tethering connection.
  3. Everything I do over Remote Desktop can be seen in person on the real displays.

Proposed solution: Somehow create a "virtual" display that's 1280x800.

  1. It's the same resolution as my MacBook's screen, so it won't have to scale.
  2. It's smaller, and will therefore use less bandwidth.
  3. It won't be a physical display, so it won't be visible in person.

Now, is there any way to produce such a "virtual display"?

  • That's weird, whenever I VNC into my 10.9 Mac it spawns a new session for the VNC client. Are you using a third party VNC server? – Kevin Chen Jan 27 '14 at 6:08
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    @KevinChen Are you? Screen Sharing always drops me into the same session and desktop that I was using in person. Or, maybe this works differently if you log out of your desktop session completely before connecting? – NReilingh Jan 27 '14 at 6:26
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You could use the Session Select feature of Apple Screen Sharing service. It allows you to log in into a "virtual" user session without showing anything on physical screen. To do so you should:

  1. create second user account and log him in "physically",
  2. connect using Screen Sharing to your iMac with your PRIMARY user credentials,
  3. Screen Sharing will provide you with 2 choices: "Share" screen with current physical user or "Log In" in a "virtual" session,
  4. select "Log In" and here you are: you have a "virtual" screen not visible to current physical user.
  5. You can now change screen resolution to match your MacBook's screen.
  • Neat! :) will changing the screen resolution effect the real displays? – Alexander Jan 27 '14 at 15:17
  • Looks like it is not as neat as it sounds. I used to use this feature on server with only one display (using cscreen for changing resolution, since there are too few available resolutions in Displays pane while in virtual session). It works almost fine with the exception of one small issue: sometimes the Screen Sharing client starts showing black screen just after resolution change. To get it back alive, you have to disconnect, wait about 30 seconds to let the hung server daemon die, and reconnect back again. – richter Jan 27 '14 at 19:24
  • But just now I checked the resolution change feature in virtual session with two monitors (a laptop and an external display). Things get much worse here: any attempt to change the resolution causes the very WindowServer to crash :-( It appears like instant logging both physical and virtual sessions out, making it impossible to change resolution. My server is 10.9.1, so it seems the best we can do is just file a bug reports to Apple :-( – richter Jan 27 '14 at 19:25
  • And no, the real display resolution is not affected. – richter Jan 27 '14 at 19:54

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