Tag Archives: VMware Horizon

Black screen when re-connect to VMware Horizon virtual desktop

27 May

We had an issue after we upgraded our EUC Stack, especially VMware App Volumes 2.14 to 2.18.1. Quite a few end-users started reporting black screen when they were trying to re-connect to their desktops post the original session launch. This would mean re-connect post breaks, endpoint screen locks, next working day re-connections, etc.

EUC Environment Details:
VMware Horizon 7.11
VMware App Volumes 2.18.1
VMware Dynamic Environment Manager 9.10
VMware Horizon Client 5.x
VMware Workspace One 3.3

Process of elimination

  • If we re-created the writable volumes of the problematic end-users the black screen issue would go away. This provided us with a clue that the problem lied with VMware App Volumes – Writable Volumes
  • No errors/failures observed within the VMware DEM/Horizon logs
  • Upgrade the Horizon Client to the latest 5.x version to remove any Client related issues
  • We already had the necessary anti-virus exclusion based on VMware Antivirus Considerations in a VMware Horizon 7 Environment

After trying out all the usual steps and avoid re-creating writable volumes for problematic end-users, we managed to open a VMware GSS case handled by Karan Ahuja(Very helpful support engineer), which ended been worked by the engineering team(Art Rothstein – Champ in AV Eng Team). Note quite alot of logs, memory dumps, and Procmon were exchanged from the problematic VM using various remote gathering techniques. Finally, the fix was determined as a writable volume snapvol.cfg exclusion. (In our case, the problem is caused by smss.exe using a copy of winlogon.exe that is on the writable volume). After putting this exclusion into all problematic end-users, they stopped seeing Black screen issues upon re-connect.

Path exclusion in writable volumes snapvol.cfg

In this blog, I am not outlining the steps on how to add the snapvol.cfg exclusion as my ex-colleague Daniel Bakshi outlines on a VMware blog post on how to do it step by step. I hope you will find this information useful if you encounter intermittent black screen issues.

Aresh Sarkari

VMware EUC – Horizon, UAG, VIDM and AppVolumes – NSX Load Balancing – Health Check Monitors

2 Feb

There is no single place to find a consolidated list of Load balancer health check monitors (aka Service Monitors in NSX) for the VMware EUC products:

I have been using VMware NSX load balancer across the board. The below details will provide an overview of what to enter for the health monitors. Note – If you are using something more meaningful  for your environment leave feedback in the comments section. I will try to implement the same and update the blog later.

VMware Unified Access Gateway (UAG)

Create a new Service Monitor under NSX and call is UAG_https_monitor. Refer to the screenshot for more details.

UAG Service Monitor

Send String: GET /favicon.ico
Response code: 200s

VMware Identity Manager or Workspace ONE Access

Create a new Service Monitor under NSX and call is VIDM_https_monitor. Refer to the screenshot for more details.

VIDM Service Monitor
Send String: GET /SAAS/auth/login
Response code: 200s

VMware Horizon Connection Servers

Update 13th Sep 2021 – For all Horizon version 7.10 and above please start using the following service monitor within NSX.

Send String: GET /favicon.ico
Response code: 200s

You can use this string for versions 7.7 or upto 7.10. Create a new Service Monitor under NSX and call is Horizon_https_monitor. Refer to the screenshot for more details.

Send String: GET /broker/xml/
Receive string: /styles/clientlaunch-default

VMware App Volumes

Create a new Service Monitor under NSX and call is AV_https_monitor. Refer to the screenshot for more details.

AV Service Monitor

I hope you will find these monitors useful in monitoring the VMware EUC products.

Aresh Sarkari