virtualbox.org

I am running a windows 8.1 guest on 13" Macbook Pro OS X Yosemite host and am not able to extend the guest to use a second monitor. I have the VM configured to use 2 monitors in the VM settings, with 3D & 2D Acceleration enabled. When I launch the guest, and try to extend the monitor to the second monitor, I get a message that "The display settings could not be saved. Please try a different combination of display settings."

I have tried every resolution listed and still no help. I have verified that the Guest Additions are installed, and have removed/re-installed them a few times based on different posts here in the forums.

This all worked initially when I set it up using the laptop display for the mac stuff, and two external monitors for the Windows 8 host. However, it stopped working after I went home and launched the VM without any external monitors connected, I lost the second VM window and have had no luck in trying to get it back.

Based on reading many different posts regarding dual monitor on VB and similar issues that Win8 users were having outside of VB, my guess was that it was trying to initialize the second monitor on the Mac retina display using the same resolution as the external monitor (1920x1014), so I tried running the guest in Full Screen on the Mac display and extending the display, but that did not help either.

This has been driving me nuts and I could really use some help as I am a Windows guy trapped in a Mac world and have no clue what I am doing.

Thanks!

I was finally able to resolve this by downgrading to VB 4.3.10. After I got it working in 4.3.10, I stepped up to 4.3.20 and it is still working. No clue why that fixed it, but since it is working, I dare not mess with that part anymore. I am having other issues with getting the guest to see the VPN connection established on the host, and a Guest Additions video driver issue that is causing Visual Studio on the guest to not work properly, but not related to the dual monitors. One step forward, two steps back it seems. With all the problems I have been having trying to get this guest set up, maybe VB is not the right tool for the job here, who knows.

I´m having the same issue. But I´m using 4.3.26 version. It was working well until tomorrow, and after a sleep proces due to a lack of energy, it stops recognizing the second monitor. Well, it really does not recognize it ever. I have a very big screen here, bigger than the mac book and it always shows windows in a letterbox fashion, and not a real full screen. very anoying. and no solutions on the horizon. Which version is the last stable and proofed for virtualizing Windows 8.1?