Apr 042020
 
VMware Horizon View Icon

I see quite a bit of traffic come in on a regular basis pertaining to issues with VMware Horizon View. A lot of these visitors either are looking for help in setting something up or are experiencing an issue I’ve dealt with. While my posts usually help these people do specific things or troubleshoot specific issues, one of the biggest issues that comes up is when users experience a VMware Horizon blank screen (or black).

This can be caused by a number of different things. I wanted to take this opportunity to go over some of the most common issues that cause this and make a master guide for troubleshooting and fixing the VMware Horizon blank screen.

Horizon Blank Screen Causes

There’s a number of different causes of a blank or black screen when connecting and establishing a VDI session to Horizon View. Click on the item below to jump to that section of the post.

Now that we have a list, let’s dive in to each of these individually. Some of these will require you to do your own research and will only guide you, while other sections will include the full fix for the issue.

VMware Tools and Horizon Agent Installation Order

When deploying the VMware Horizon View agent, you are required to install the agent, along with VMware tools in a specific order. Failing to do so can cause problems, including a blank screen screen.

The installation order:

  1. Install GPU/vGPU drivers (if needed)
  2. Install VMware Tools Agent
  3. Install the VMware Horizon Agent
  4. Install the VMware User Environment Manager Agent (if needed)
  5. Install the VMware App Volumes Agent (if needed)

It is important to also consider this when upgrading the agents as well.

Network ports are blocked (Computer Firewall, Network Firewall)

For the VMware Horizon agent to function properly, ports must be accesible through your firewall, whether it’s the firewall on the VM guest, client computer, or network firewall.

The following ports are required for the VMware Horizon Agent when connecting directly to a View Connection Server.

DestinationNetwork ProtocolDestination PortDetails
Horizon Connection ServerTCP443Login, authentication, and connection to the VMware Connection Server.
Horizon AgentTCP22443Blast Extreme
UDP22443Blast Extreme
TCP4172PCoIP
UDP4172PCoIP
TCP3389RDP (Remote Desktop Protocol)
TCP9427Client Shared Drive redirection (CDR) and Multi-media redirection (MMR).
TCP32111USB Redirection (Optional), can be incorporated in to the Blast Extreme connection.
Network Ports Required for VMware Horizon View to View Connection Server

The following ports are required for the VMware Horizon Agent when connecting through a VMware Unified Access Gateway (UAG).

DestinationNetwork ProtocolDestination PortDetails
Unified Access GatewayTCP443Login, authentication, and connection to the Unified Access Gateway. This port/connection can also carry tunneled RDP, client drive redirection, and USB redirection traffic.
TCP4172PCoIP via PCoIP Secure Gateway
UDP4172PCoIP via PCoIP Secure Gateway
UDP443Optional for Login traffic. Blast Extreme will attempt a UDP login if there are issues establishing a TCP connection.
TCP8443Blast Extreme via Blast Secure Gateway (High Performance connection)
UDP8443Blast Extreme via Blast Secure Gateway (Adaptive performance connection)
TCP443Blast Extreme via UAG port sharing.
Network Ports Required for VMware Horizon View to VMware Unified Access Gateway (UAG)

You’ll notice the ports that are required for Blast Extreme and PCoIP. If these are not open you can experience a blank screen when connecting to the VMware Horizon VDI Guest VM.

For more information on VMware Horizon 7 network ports, visit https://techzone.vmware.com/resource/network-ports-vmware-horizon-7.

DNS Issues

While VMware Horizon View usually uses IP address for connectivity between the View Connection Server, guest VM, and client, I have seen times where DNS issues have stopped certain components from functioning properly.

It’s always a good idea to verify that DNS is functioning. DNS (forward and reverse) is required for VMware Horizon Linux guests VMs.

Incorrectly configured Unified Access Gateway

A big offender when it comes to blank screens is an incorrectly configured VMWare Unified Access Gateway.

Sometimes, first-time UAG users will incorrectly configure the View Connection server and UAG.

When configuring a UAG, you must disable both “Blast Secure Gateway”, and “PCoIP Secure Gateway” on the View Connection Server, as the UAG will be handling this. See below.

Picture of the Secure Gateway settings on VMware Horizon View Connection Server when used with VMware UAG.
Secure Gateway Settings on View Connection Server when used with UAG

Another regular issue is when admins misconfigure the UAG itself. There are a number of key things that must be configured properly. These are the values that should be populated on the UAG under Horizon Settings.

Connection Server URLhttps://ConnectionServerIP:443
Connection Server URL Thumbprintsha1=SSLTHUMPRINT
(Thumbprint of the SSL certificate your View Connection Server is using)
PCOIP External URLUAG-EXTERNALIP:4172
Blast External URLUAG-InternetFQDN:443
Tunnel External URLUAG-InternetFQDN:443

You must also have a valid SSL certificate installed under “TLS Server Certificate Settings”. I’d recommend applying it to both the admin and internal interface. This is a certificate that must match the FQDN (internal and external) of your UAG appliance.

Once you’re good, you’re green!

Picture of the VMware UAG interface showing all green (functioning).
VMware Unified Access Gateway showing valid

You should always see green lights, all protocols should work, and the connections should run smooth. If not, troubleshoot.

GPU Driver Issue

When using a GPU with your VM for 3D graphics, make sure you adhere to the requirements of the GPU vendor, along with the VMware requirements.

Some vendors have display count, resolution, and other limits that when reached, cause Blast Extreme to fail.

An incorrectly installed driver can also cause issues. Make sure that there are no issues with the drivers in the “Device Manager”.

VMware documents regarding 3D rendering:

Blast Extreme log files can be found on the guest VM in the following directory.

C:\ProgramData\VMware\VMware Blast\

Looking at these log files, you can find information that may pertain to the H.264 or display driver issues that will assist in troubleshooting.

VMware Tools

A corrupt VMware tools install, whether software or drivers can cause display issues. Make sure that the drivers (including the display driver) are installed and functioning properly.

It may be a good idea to completely uninstall VMware Tools and re-install.

If you’re experiencing display driver issues (such as a blank screen), before re-installing VMware Tools try forcibly removing the display driver.

  1. Open “Device Manager”
  2. Right click on the VMware Display adapter and open “Properties”
  3. On the “Driver” tab, select “Uninstall”
  4. Check the box for “Delete the driver software for this device”.

This will fully remove the VMware driver. Now re-install VMware Tools.

Horizon Agent

Often, re-installing the Horizon Agent can resolve issues. Always make sure that VMware Tools are installed first before installing the Horizon Agent.

Make sure that if you are running 64-bit Windows in the VM then you install and use the 64-bit Horizon Agent.

You may experience issues with the “VMware Horizon Indirect Display Driver”. Some users have reported an error on this driver and issues loading it, resulting in a blank screen. To do this, I’d recommend forcibly uninstalling the driver and re-installing the Horizon Agent.

To forcibly remove the “VMware Horizon Indirect Display Driver”:

  1. Open “Device Manager”
  2. Right click on the “VMware Horizon Indirect Display Driver” and open “Properties”
  3. On the “Driver” tab, select “Uninstall”
  4. Check the box for “Delete the driver software for this device”.

Now proceed to uninstall and reinstall the Horizon View Agent.

On a final note, when running the Horizon Agent on Horizon for Linux, make sure that forward and reverse DNS entries exist, and that DNS is functioning on the network where the Linux VM resides.

Video Settings (Video Memory (VRAM), Resolution, Number of Displays)

When experiencing video display issues or blank screens on VMware Horizon View, these could be associated with the guest VM’s memory, video memory (VRAM), display resolution, and number of displays.

Make sure you are adhering to the specifications put forth by VMware. Please see the following links for more information.

Protocol

When troubleshooting blank screens with VMware Horizon, you need to try to identify if it’s specific to the guest VM, or if it’s associated with the connection protocol you’re using (and the route it takes whether through a Connection Server, or UAG).

Always try different protocols to see if the issue is associated with all, or one. Then try establishing connections and find if it’s isolated direct to the Connection Server, or through the UAG.

If the issue is with a specific protocol, you can view the protocol log files. If the issue is with the UAG, you can troubleshoot the UAG.

Log files can be found in the following directory:

C:\ProgramData\VMware\

HTTPS Proxy and redirection issues

If you are connecting through a network that does passive HTTPS scanning or that uses a proxy server, you may experience issues with inability to connect, or blank screens.

You’ll need to modify your firewall or proxy to allow the VMware connection and open the required ports for VMware Horizon View.

Login banner or disclaimer (PCoIP)

I haven’t seen or heard of this one in some time, but when using VMware Horizon with PCoIP, sessions can fail or show a blank screen when the legal disclaimer login banner is used.

For more information on this issue, and how to resolve or workaround, visit https://kb.vmware.com/s/article/1016961.

Old version of Horizon View

It never stops surprising me how old some of the VMware Horizon View environments are that some businesses are running. VMware regularly updates, and releases new versions of VMware Horizon View that resolve known issues and bugs in the software.

While it may be difficult, simply upgrading your VMware Horizon environment (VMware vSphere, View Connection Server, VMware Tools, VMware Horizon Agent) can resolve your issues.

Blank Screen connecting to Physical PC running Horizon Agent

When you install the VMware Horizon Agent on a Physical PC, you may encounter issues with a blank screen.

This is usually caused by:

After troubleshooting these issues, you should be able to resolve the issue.

Conclusion

As you can see there are a number of different things that can cause Horizon View to show a blank screen on login.

Let me know if this helped you out, or if you find other reasons and feel I should add them to the list!

  3 Responses to “VMware Horizon Blank Screen”

  1. This is a great list.
    We often run into black/blank screens. Sometimes we have to restart the VM (full clone/linked clone), sometimes we have to restart the connecting device, sometimes we have to restart the hotspot/modem or whatever method they are connecting thru. Onetime we even had the user upgrade the horizon client. It’s very annoying to say the least, since it happens at random. I believe it’s network issues that cause this most of the time.

  2. I wanted to thank you for taking the time to write these posts. They really helped me troubleshoot my issues with Horizon. The information and suggestions really helped point me in the right direction to find the solution to my problem.

  3. Hey Bob,

    I’m glad it helped and thanks for taking the time to leave a comment. I always appreciate the feedback!

    Stephen

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