Hyper-V Missing VMs

Over the past 6 months I installed 4 Server 2019 Hyper-V hosts for various clients. After several months with no problems, following a reboot, all running VM’s completely disappeared from the Hyper-V management console and were not accessible from the network using management tools, file shares, remote desktop, or even pings. Oddly, shut down or saved VM’s were present.

When this first happened I was shocked. The VHDX files were all present so I could create a new VM, but that didn’t seem practical. Googling showed that this can happen if the Hyper-V Virtual Machine Management service did not start, but in my case it had. I tried restarting the service, the VM’s instantly reappeared, and were in a running state with boot up almost complete.

This issue over the coming months started happening on other 2019 servers and after every reboot, planned or due to a power outage, I had to connect to the host and restart the Hyper-V Virtual Machine Management service.

Further Googling this issue brings up suggestions of corrupt VM configuration files, granting “NT Virtual Machine\Virtual Machines” the “logon as a service right”, doing the same with group policy, and other suggestions, but where restarting the service would resolve in every case I assumed there was not a configuration issue.

In the end setting the Hyper-V Virtual Machine Management service start up type to “Automatic (delayed start)” resolved the problem on all machines, though it resulted in a slightly longer boot time for the VMs.

All of thee servers worked fine for a few months so I assume the problem was due to a Windows update but to date I have found no actual cause. Also, I can confirm this only occurs on my 2019 Hyper-V hosts. There are no issues with Server 2016 or earlier servers.

Hyper-V restart

Update: Oct 2020. I had another server with the same issue. O/S had been installed 8 months prior and no updates applied in recent months. Setting the service as delayed start did not resolve. I had to create a scheduled task to run 10 minutes after boot up. 5 minutes did not work. The scheduled task simply pointed to a batch file with the following. (the ping command just delays the process to be sure Net Stop completes before the next line).

Net Stop VMMS
ping -n 10 127.0.0.1
Net Start VMMS
Exit

Recently found on 3 two month old HP computers users could not open Office documents that were received as attachments to e-mails within Outlook. After troubleshooting, discovered it was due to an HP add-on utility “HP Single Click” a security app provided with many HP PCs. This can simply be uninstalled from Programs and Features, however any open apps that use it must be closed. A reboot will insure this. Also a reboot is required after uninstalling. Presumably this was caused by a windows or HP update as it had not been a problem in the past. Perhaps more recent updates have resolved the problem.

Intro to PowerShell

For those not knowing where to start with learning PowerShell, Netwrix is offering a free 47 page document “Windows PowerShell Tutorial for Beginners” which includes numerous simple, common, tasks.  One of the best intros I have seen.

https://try.netwrix.com/powershell-tutorial

I had a client where Adobe Acrobat XI Standard, on Windows 10, worked flawlessly for several years, but recently documents would open and then after a couple of seconds close with no warning.  Reinstallation and reactivating did not solve the problem nor did many Internet search results such as registry edits.

What did work was to open Adobe and very quickly, before it closed, click  “Help” on the menu bar and then select “Check for updates”.  It did find an update, download, and install.  It worked fine after that.  I suspect a compatibility issue with a recent Windows update may have caused the problem.

A client had a 4 hour power outage today.  Though the Hyper-V host, which was connected to a business class UPS, rebooted as it should, none of the VMs came back on line. The Hyper-V management console showed “No virtual machines were found on this server”.

capture1

After researching several solutions before simply recreating the virtual machines I restarted the “Hyper-V Virtual Machine Management service”, which was already running.  Instantly all VM’s reappeared and started up.  Perhaps this may assist others down the road.

This is a must have pdf reference file: 

An amazing, free, current, searchable, compilation of hundreds Windows commands with explanations, syntax, and examples of their use.  And, it’s free !

https://www.microsoft.com/en-us/download/details.aspx?id=56846

Windows Commands

It seems recently many users are receiving an error logging into Remote Desktop Servers (Terminal Servers) from off-site. The error reads:

KB4103725

An authentication error has occurred.
The function request is not supported.
Remote computer <ServerName>
This could be due to CredSSP encryption oracle remediation.
For more information, see https://go.microsoft.com/fwlink/?linkid=866660

This is a result of a March 13th update. The previous error message was shorter, but an Apr 17 update elaborated the error message to read as above.

The link explains how to resolve using group policy but the simple fix, as of May 8th, is to apply the KM4103725 monthly rollup update. This will require a reboot on most servers, but should resolve the problem once complete.

 

It seems Windows 10 Update fails sometimes, especially with the Fall Creators Update.  It continuously wants to install, you approve, it runs, and fails, often with error code 0xc1900208.   

In troubleshooting I have found most of the time it will install if you click the “Update now” button form the Creators Update Web page.  It seems to check for compatibility, make any adjustments, then Install.https://www.microsoft.com/en-us/software-download/windows10 

Should that fail to work, you can download the Windows 10 Update Troubleshooter, which will troubleshoot, and offer to repair any issues found.  There is also a troubleshooter for Win  7 and 8.https://support.microsoft.com/en-us/help/4027322/windows-update-troubleshooter 

However, I also recently read about an issue with attached USB drives oddly causing the update to fail.  Recently,  on a PC on which I tried all of the aforementioned options, and had no attached USB devices, I discovered a DVD in the drive.  Once ejected the update installed without a problem.  This strikes me as very bizarre, but perhaps the update searches other available drives for some reason. 

Therefore; I recommend if having issues with Windows updates, try disconnecting any USB devices such as external drives, thumb drives, phones which may be charging, and possibly even USB printers, and don’t forget to check the DVD tray, just in case.

Adobe Strange Characters

Have you ever opened an Adobe document and been surprised to see hieroglyphic-like, unrecognizable,  characters?

Adobe garble

Having seen this a few times and having found dozens of solutions on the internet, some of which seem rather complex, I did a little tinkering.  It seems the common denominator is one simple change; allowing “document fonts”.   I confess I have not run across this with Adobe Acrobat Reader, but if Adobe Standard or Pro, there will be an Adobe “Printer”.  To resolve the problem……….

 

  • Windows 7/8: Open Control Panel and then Devices and Printers Right click on the Adobe “printer” and choose Printer properties.
  • Windows 10: In the Cortana Search box type printers and click enter, which should open the Printers and Scanners window. Click on the Adobe “printer” and 3 buttons should appear, click manage, then Printer Properties
  • Click the “Preferences” button near the bottom
  • Choose the “Adobe PDF Settings” tab
  • Uncheck the box “rely on system fonts only, do not use document fonts”
  • Click Apply, OK, and close all windows
  • This requires a restart to take effect.

 

 

On several systems over the past year I have seen the C:\Windows\Temp folder filling up with large .cab files generated by the system, on a semi-regular bases.  This continues until there is no available drive space and the system becomes unusable.

The short term solution is to just delete all of the files but the problem returns after weeks or months, depending on the initial free drive space.

It seems this is caused by a large log file within the C:\Windows\Logs\CBS folder.  To resolve I created a folder C:\Windows\Logs\CBS_Archive and moved all  CbsPersist_file_number.log files, older than 10 days, to the archive folder.  This seems to have resolved the issue.

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