Screen count not working, and a fix

[hangerglide]

Over the last 6 months or so I ran into an issue with multiple monitors. I'd guess this is some kind of a minor bug. I had a quick look for like kind issues here and didn't run across any but I'd guess it has been reported before. I'm running vbox 6.0.4 at this moment.

My setup is host Windows 7 pro x64; guests that had this issue are windows 7 or 10 pro.

Each of the vms were configured to have two monitors; I have to physical monitors. What happened is that one day the vms would launch with only one monitor on the guest. I found if I pushed the windows 7 vm to 3 monitors in vbox it'd run with two hosts. With the windows 10 vm, that trick didn't work.

The fix turned out to be simple: set the vm back to 1 monitor, start, shutdown, set to 2 monitors. Both of these vms are back to running with 2 monitors.

I'm reporting this here in case it's news to anyone, and in the hope that I can contribute something after receiving so much quality assistance over the years.

[hangerglide]

Victory is not compete...one vm (windows 10 pro x64, with vbox setting to match) will still not go to 2 monitors. Any suggestions?

[hangerglide]

Any ideas on this?

[andyp73]

Any ideas on this?

With the limited amount of information available, not really. Can you provide the VBox.log file for one of the failing guests and also the .vbox file (the guest recipe). With those we may be able to get a better idea of what VirtualBox is supposed to be doing and what the reality looks like.

-Andy.

[hangerglide]

ok, here you go

[hangerglide]

Any ideas on this? (take 2)

[andyp73]

The log file shows that the guest is configured with 2 monitors and there are several references in the log to both screen 0 and screen 1. The only thing I can suggest trying is enabling 2D and 3D acceleration and seeing if that changes the situation.

-Andy.

[hangerglide]

Thanks for those suggestions. However they don't make the 2nd monitor appear.

So this is an authentic bug.

[socratis]

<Display VRAMSize="128" monitorCount="2"/>

<ExtraDataItem name="GUI/LastGuestSizeHint" value="1735,989"/>
<ExtraDataItem name="GUI/LastGuestSizeHint1" value="640,480"/>
<ExtraDataItem name="GUI/LastGuestSizeHint2" value="640,480"/>

<ExtraDataItem name="GUI/LastNormalWindowPosition" value="135,75,1735,1031"/>
<ExtraDataItem name="GUI/LastNormalWindowPosition1" value="640,340,640,480"/>
<ExtraDataItem name="GUI/LastNormalWindowPosition2" value="640,340,640,480"/>
<ExtraDataItem name="GUI/LastNormalWindowPosition3" value="640,340,640,480"/>

Those shouldn't be there (the red ones) and secondly they're not your typical size. So, I'm not sure how you ended up like this, but you need to shutdown the VM (completely, not saved or paused) and clear them. And for good measure, clear them all.

The following assumes that you've installed VirtualBox in its default "C:\Program Files\Oracle\VirtualBox", if not, adjust accordingly:

• 
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastGuestSizeHint"
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastGuestSizeHint1"
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastGuestSizeHint2"
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastNormalWindowPosition"
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastNormalWindowPosition1"
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastNormalWindowPosition2"
  "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata "GUI/LastNormalWindowPosition3"

This will reset all the values, well, actually delete them. Try again and if it fails then post the new set of logs. ZIPPED please.

And then we get to do some more tests, and some more, to see if we can call it "an authentic bug", I don't really like premature naming without a proper investigation...

PS. You don't have to do this on a computer with 2 screens or more, 1 is enough. As long as you get to see the "monitor" from within the guest, a 2nd window will show up in the host, maybe underneath the 1st window, but for testing purposes, I don't really care.

[hangerglide]

Sure, no premature bug naming <g>. I can clear all of those values. Then the next set of lines that you list are at the command line; I'll try.

In case the original email got skipped over I'll reiterate that I had a handful of vms that started behaving this way. Some of them were fixed by setting the monitor count to 1, starting, and then setting to 2. Also one of them originally responded to getting the monitor count to 3; then it would show 2. When it went back to running 1 screen I tried setting to 4, but that didn't help.

[socratis]

If you want 2 monitors, stick with 2 monitors. Don't go randomly changing a number of variables to a problem. That makes it really, really difficult to figure out what's going on, who's the culprit. You're creating a Multivariable calculus problem, you don't want to get into that trust me, especially tensors, that's how I got my first grey hair! At 23!!!

[hangerglide]

I only used the GUI to adjust the monitors, I didn't manually adjust the xml. Just trying to get it to work properly. The origin of the problem is unknown. All of the effected vms had been running fine for 1+ years when this issue manifested; and the issue cropped up on each vm at a different time, which would make me think it wasn't due to a vbox update. These are all on the same host.

[hangerglide]

Hmm. I used these commands; the machine name is correct

"E:\virtualbox\VBoxManage" setextradata "win 10 pro 02 (o2016)" "GUI/LastGuestSizeHint" "1280,960"
"E:\virtualbox\VBoxManage" setextradata "win 10 pro 02 (o2016)" "GUI/LastNormalWindowPosition" "486,75,1280,1066"

I expected that this would get me 1 monitor because I interpret that when you listed 3 hints and 4 positions it was only because the original xml had that from my attempted workarounds. From there I hoped to be able to set it to 2 screens and have it work. However the after staring the vbox gui is still reports 2 screens; and only runs 1.

I will post new logs.

[hangerglide]

zipped files

[socratis]

Who exactly told you to use these commands? What are you trying to do? Sabotage the whole thing?

Please do not do things out of order, if you want to continue receiving help. I told you to simplify things, not to start intervening without having a clue what you're doing. Please... for the love of bytes!!!

RESET the values by deleting them again. Then let VirtualBox set them automatically. Do not mess with it manually!