Black Screen Issues with 7.x VDA
Over the last 7 months we have spent an enormous amount of time working with Citrix on a problem that we just couldn’t shake. When we started our migration process from XenDesktop 5.6 to 7.1 we got a very nasty error. Users would make a successful ICA connection but the screen would stay totally black. Rebooting would sometimes correct it for a time, but not permanently. Reinstalling the VDA did the same. We tried all the different VDA versions that came out and in every case we could reproduce the issue. The number of hours we spent with Citrix Escalation is pretty staggering and ultimately it took direct interaction with the developers to solve it.
First, many thanks to our Citrix TRM for staying on top of this. It dragged out a considerably long time (far longer than it should have frankly) but he kept forcing everyone to respond and eventually find the root cause. Based on the Citrix forums, it appears many people have experienced this issue without a true permanent fix so I hope this helps another org save a ton of pain! This issue manifested on both ESX and HyperV and frankly has nothing to do with the hypervisor. It has to do with how the Video Memory is allocated to the Citrix Video Driver at session launch. Because of the order of memory allocation it can become fragmented and cause the black screen.
The fix is two parts. First, if you are using the 7.1 VDA you need to make sure you have ICAWS750WX86008.msp installed as a hotfix. Without this the second part of the fix doesn’t matter. That file is not needed with the 7.6 VDA (and I THINK not with the 7.5 VDA but I haven’t tested). The second part of the fix is two registry entries:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\vbdenum]
“Start”=dword:00000001
“MaxVideoMemoryBytes”=dword:06000000
“Group”=”EMS”
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\vd3d]
“MaxVideoMemoryBytes”=dword:00000000
You can change the MaxVideoMemoryBytes field to be higher as well. What happens is it grabs the memory defined in that key earlier in the process as a contiguous space so that it is not fragmented. Poof, no more black screens. Those keys are part of the 7.6 VDA but you still want to look at the MaxVideoMemoryBytes and adjust according to your own requirements.
*Update* I’m hearing that they aren’t actually in 7.6. So if you experience the problem I suggest adding them.
VDA black screen, VDA memory issue, XenDesktop 7.1, XenDesktop black screen
I am running 7.6 VDA’s on Windows Server 2012 R2, but I do not see the registry keys you mention. No vbdenum or vd3d in HKLM\System\CurrentControlSet\Services\
Sorry too many things on the brain… Response was to another comment. If you don’t see those reg keys I suggest adding them. Although I have never seen a black screen with Server sessions it won’t hurt to preallocate the video memory.
Hi, it works on Win8, XD 7.6. Thank you.
HI,
I can confirm this works on Win7 X64 XD 7.5 with CAWS750WX64008.msp
Thanks so much for posting this. I had a case open with Citrix regarding this exact
issue and wasn’t getting anywhere fast. You just made my day!
cheers
Hi.
I have xendesktop 7.6 and VDA installed on Windows 7 machines. However I DO NOT have those keys1!
any ideas?
Are you experiencing the blackscreen issue? If so I would definitely give them a try.
Thanks but what I meant was that I don’t have these reg keys to begin with..
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\vbdenum
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\vd3d
[…] Citrix Tips – Black Screen Issues with 7.x VDA: Users would make a successful ICA connection but the screen would stay totally […]
Is this a String :
“Group”=”EMS”
[…] Citrix Tips – Black Screen Issues with 7.x VDA: Users would make a successful ICA connection but the screen would stay totally […]
What hyper-visor are you running?
We had the the same Black Screen issue with VMware 5.0u3 running Citrix 7.1. The fix we found was to uninstall both VMware Tools and Citrix VDA. Reinstall VMware Tools WITHOUT the SVGA driver, and install the Citrix VDA normally. As soon as we did that we no longer had the black screen issue.
I’m curious if this will allow us to put everything back to “normal”.
That was one of the first things tried 😉 This was also ESX 5.0u3 and on 5.5 as well.
Good to know! Thanks.
I am also running a XD/XA 7.6 & PVS 7.6 environment and we had the “Black Screen” issue. My immediate fix was to also uninstall the VMware SXVGA driver. That prevented the Black Screens, but the long term fix was Reverse imaging and updating the WMware Tools to 9.4.12. Interestingly enough, the Registry keys mention in this article are already set in my PVS images without manual entry. Although the MaxVideoMemoryBytes key is set at 0x04000000. I may try bumping it up since we had 2 more random “Black Screen” across a two month period. Before that it was over half the organization, so I’ll take 1 a month compared to 100+ a day.
Hi there
I have a similar issue where the VDI ist completely frozen after the connection attempt. I have to reboot to try again.
Do you experience the same?
thank you
David
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I have 2012 R2 vda met 7.7 version but don’t have the registry keys
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\vbdenum
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\vd3d
Anyone any idea
[…] Citrix Tips – Black Screen Issues with 7.x VDA: Users would make a successful ICA connection but the screen would stay totally […]
[…] Citrix Tips – Black Screen Issues with 7.x VDA: Users would make a successful ICA connection but the screen would stay totally […]
[…] Citrix Tips – Black Screen Issues with 7.x VDA: Users would make a successful ICA connection but the screen would stay totally […]
when i am launching console of VDI , machine stuck at black screen and not going ahead.