In response to COVID 19, VMware has extended their VMware Horizon 7 trial offering up to 90 days and includes 100 users. This includes both VMware Horizon 7 On-Premise, as well as VMware Cloud on AWS.
This is great if you’re planning or about to implement and deploy VMware Horizon 7.
In it’s simplest form, Horizon 7 allows an organization to virtualize their end user computing. No more computers, no more desktops, only Zero clients and software clients. Not only does this streamline the end user computing experience, but it enables a beautiful remote access solution as well.
And Horizon isn’t limited to VDI… You can install the VMware Horizon Agent on a Physical PC so you can use VDI technologies like Blast Extreme to remote in to physical desktops at your office. It makes the perfect remote access solution. Give it a try today with an evaluation license!
In all my years assisting and providing support with VMware Horizon, one of the most common problems that customers report with their VDI implementations, is the VMware Horizon Blank Screen.
When a user is presented with a blank or black screen when using the VMware Horizon Client, the problem can be caused by a number of different things. In this post, I will address and provide solutions for some of the common issues that cause the VMware Horizon blank screen.
VMware Horizon Blank screen issue
This troubleshooting guide applies to VMware Horizon 8, VMware Horizon 7, as well as earlier versions of VMware Horizon.
VMware 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:
Install GPU/vGPU drivers (if needed)
Install VMware Tools Agent
Install the VMware Horizon Agent
Install the VMware User Environment Manager Agent (if needed)
Install the VMware App Volumes Agent (if needed)
It is important to also consider this when upgrading the agents as well. When upgrading VMware Tools, it is recommended to re-install the Horizon agent in versions up to and including Horizon 8 2103. As of Horizon 2106 and later, you no longer need to re-install the Horizon Agent when performing a VMware Tools upgrade.
Network ports are blocked (Computer Firewall, Network Firewall)
For the VMware Horizon agent to function properly, ports must be accessible 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.
Destination
Network Protocol
Destination Port
Details
Horizon Connection Server
TCP
443
Login, authentication, and connection to the VMware Connection Server.
Horizon Agent
TCP
22443
Blast Extreme
UDP
22443
Blast Extreme
TCP
4172
PCoIP
UDP
4172
PCoIP
TCP
3389
RDP (Remote Desktop Protocol)
TCP
9427
Client Shared Drive redirection (CDR) and Multi-media redirection (MMR).
TCP
32111
USB 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).
Destination
Network Protocol
Destination Port
Details
Unified Access Gateway
TCP
443
Login, authentication, and connection to the Unified Access Gateway. This port/connection can also carry tunneled RDP, client drive redirection, and USB redirection traffic.
TCP
4172
PCoIP via PCoIP Secure Gateway
UDP
4172
PCoIP via PCoIP Secure Gateway
UDP
443
Optional for Login traffic. Blast Extreme will attempt a UDP login if there are issues establishing a TCP connection.
TCP
8443
Blast Extreme via Blast Secure Gateway (High Performance connection)
UDP
8443
Blast Extreme via Blast Secure Gateway (Adaptive performance connection)
TCP
443
Blast 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.
Certain types of IPS (Intrusion Prevention Service) can also intercept and block traffic. IPS may cause intermittent issues.
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 both internally and externally. DNS (forward and reverse) is required for VMware Horizon Linux guests VMs.
XDR, EDR, and AV Platform causing momentary blank screen at logon
When using an XDR (Extended Detection and Response), EDR (Endpoint Detection and Response), or special AV solution with non-persistent desktops, one may experience a momentary blank screen on user session logon. I have observed this with Sophos XDR as well as Cortex XDR, with blank screens varying from 10-30 seconds on user login.
Removal of the platform can reduce the momentary blank screen down to 1-5 seconds.
I highly recommend configuring and tweaking policies as much as possible to enhance and optimize your environment. There will always be a trade off of performance for security, and the decisions should be made by those in the organization who make cyber security related decisions.
Incorrectly configured Unified Access Gateway
A big offender when it comes to blank screens is an incorrectly configured VMWare Unified Access Gateway for VMware Horizon.
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.
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 URL
https://ConnectionServerIP:443
Connection Server URL Thumbprint
sha1=SSLTHUMPRINT (Thumbprint of the SSL certificate your View Connection Server is using)
PCOIP External URL
UAG-EXTERNALIP:4172
Blast External URL
UAG-InternetFQDN:443
Tunnel External URL
UAG-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!
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”.
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.
When using GPUs such as Nvidia GRID and AMD MxGPU, it is recommended to disable the VMware SVGA 3D Driver and adapter inside of Device Manager after you install the applicable GPU drivers.
NVIDIA vGPU Issues
You may be experiencing issues related to the NVIDIA vGPU platform, either inside of the VM guest, or on the VMware ESXi host.
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.
Open “Device Manager”
Right click on the VMware Display adapter and open “Properties”
On the “Driver” tab, select “Uninstall”
Check the box for “Delete the driver software for this device”.
This will fully remove the VMware driver. Now re-install VMware Tools.
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”:
Open “Device Manager”
Right click on the “VMware Horizon Indirect Display Driver” and open “Properties”
On the “Driver” tab, select “Uninstall”
Check the box for “Delete the driver software for this device”.
Now proceed to uninstall and reinstall the Horizon View Agent.
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.
Also, as a reminder, it is recommended that you re-install the Horizon agent in versions up to and including Horizon 8 2103 after upgrading VMware Tools. As of Horizon 8 2106, you no longer need to re-install the Horizon Agent when performing a VMware Tools upgrade.
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.
vSphere Video RAM Configuration for VMware Horizon
If you do not have enough Video RAM (VRAM) allocated to the virtual machine and/or you have too many displays (multi-monitor), then you can experience the blank screen with Horizon.
Make sure you are adhering to the specifications put forth by VMware. Please see the following links for more information.
While this isn’t likely to cause a blank screen issue (it can though), it’s always a good idea to set your image to a lower resolution before snapping or converting to a template for deployment.
It’s a lot easier for the VMs to start using lower resolution and VRAM (Video Memory) and then increase to what’s needed, instead of starting at a crazy high resolution and then getting adjusted down.
I consider it a good practice to reduce the graphics resolution before creating and deploying the image to the desktop pools.
Protocol
When troubleshooting blank screens with VMware Horizon, you need to try to identify whether 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 and/or transparent HTTPS scanning or 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 and create an exception not to touch or manipulate the VMware Horizon related traffic.
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 on the Windows instance (Windows 7, Windows 10, or Windows 11).
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 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 often resolve many issues.
Blank Screen connecting to Physical PC running Horizon Agent
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. It’s always best to try to understand how the technology works, and establish where the failure points are.
Let me know if this helped you out, or if you find other reasons and feel I should add them to the list!
In response to the COVID19 crises and to help customers and partners, HPE is providing a free iLO Advanced license for your HPE Servers.
These licenses are full licenses that are valid until January 1st, 2021. This means you’ll have the full Integrated Lights-Out product through the end of the 2020 year.
This link will take you to sign up for a HPE iLO Advanced trial license. After filling out the form, you’ll be able to download your iLO welcome letter, which includes your iLO key (that is valid through 2020), and instructions.
This is awesome, and will definitely help out a ton of IT administrators this year to remotely manage, monitor, and maintain their servers.
One of the most widely used applications suite is Microsoft Office, particularly Microsoft Office 365.
In order to deploy Microsoft Office 365 in a Remote Desktop Services environment, a number of requirements must be met. There is also special instructions which must be followed to properly deploy it.
After reading and completing the steps in this blog post and deploying Office 365, you can head over to my guide on how to Configure Office 365 in a Remote Desktop Services Environment using GPOs to pre-configure Microsoft Office and it’s applications for when your users log in.
What’s required
To deploy Microsoft Office 365 on a Remote Desktop Services Server, you’ll need:
A Remote Desktop Services Server (Configured and Running)
Microsoft 365 Apps for Enterprise (formerly named as Office 365 ProPlus)
Licensing
Special attention must be paid to licensing. In order to properly license and activate Office 365, you’ll need one of the following products that supports Shared Computer Activation:
Microsoft 365 Apps for Enterprise (formerly known as Office 365 ProPlus)
Microsoft 365 Standard, Office 365 Business, Office 365 Business Premium, and Office 365 Business Essentials cannot be used as they do not include or support Shared Computer Activation.
An exception is made for Microsoft 365 Business Premium which actually includes Microsoft 365 Apps for Business, but doesn’t support enabling “Shared Computer Activation” via Group Policy Objects and must be done using the XML configuration file method.
Installing Office 365
Once you have the proper licensing and you’re ready to proceed, you can start!
To download the 32-bit version or enterprise version, use one of the other xml files that are in the directory.
There will be no output and it will take a while so be patient.
Now we want to open the xml file we previously used (in our case “configuration-Office365-x64.xml”) and add the following lines to the file right above the final line (right above </Configuration>):
Office 365 should now install silently, and then afterwards you should be good to go!
When a user logs in for the first time it will ask them to activate on their account. The user must have a license attached to their Office 365 account.
I found out today that some time ago, the G729 codec was released from all patents, and is now available free of charge to use on FreePBX (and probably Asterisk).
On fresh installation of the FreePBX SNG distribution, the G729 codec is pre-installed and ready to go out of the box, however if you have an older system that you have been maintaing and upgrading, G729 is not automatically installed.
As of version SNG7-PBX-64bit-1712-2 (with FreePBX 14.0.1.22) which was released on December 21st, 2017 the codec is included.
Open Source G729 codec is now present on installation
Older installations can activate it with the 'g729' command
How to install G729
If you have an older install that you have been updating to the latest release, as per the release notes you must run the “g729” command. This will tell you if it is, or is not installed. If it is not installed, it will advised you to run the “yum -y install asterisk13-g729” command.
I ran the commands and installed the G729 codec on my system running SNG7-PBX-64bit-2002-2 (FreePBX Version 15.0.16.42, OS Version: 12.7.6-2002-2.sng7).
[root@pbx01 ~]# g729
The Open Source G729 code is not installed.
You can install it with the following command:
yum -y install asterisk13-g729
[root@pbx01 ~]# yum -y install asterisk13-g729
The package then installed, I restarted the PBX, and g729 was available to use. I tested and it works great!
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