Solved Hyper-V error

Winuser · Jan 1, 2022

I tried running my Win 10 Hyper-V VM this morning and this error popped up. I haven't used Hyper-V in a while, so I don't know when the problem started. Anyone have any suggestions on how to fix this?

cereberus · Jan 1, 2022

That usually means settings reference a vhd or iso that has been moved or deleted.

Slavic · Jan 1, 2022

Yes, you can re-configure the VM in settings and point at new ISO location. If you used ISO only to install Windows on virtual disk and it is no longer required after installation, you can remove this file from configuration, even with its controller.

Winuser · Jan 2, 2022

cereberus said:
That usually means settings reference a vhd or iso that has been moved or deleted.

That was my first thought. The file is right where it should be. I can't even import the saved VM. I'm thinking a setting got turned off.

cereberus · Jan 3, 2022

What have you set aa your default locations for the virtal machines amd the virtual jad drives?

The. export, if importing, you have to point to the virtual machines folder. You seem to be showing the virtual hard drive folder. I do not see how this is connected to previous issue of not finding iso.

Slavic · Jan 3, 2022

If the VHD file isn't damaged and access isn't blocked by lack of permissions, the virtual machine can be recreated anew. It's quite easy process. But if VHD is damaged, situation is worse, you need to re-download it at best or create a new VHD and re-install a system at worst.

Winuser · Jan 3, 2022

cereberus said:
What have you set aa your default locations for the virtal machines amd the virtual jad drives?

The. export, if importing, you have to point to the virtual machines folder. You seem to be showing the virtual hard drive folder. I do not see how this is connected to previous issue of not finding iso.

I have pointed it to every folder and sub folder where I exported the VM with the same results. Were should I point Hyper-V to open the VM?

Winuser · Jan 3, 2022

Slavic said:
If the VHD file isn't damaged and access isn't blocked by lack of permissions, the virtual machine can be recreated anew. It's quite easy process. But if VHD is damaged, situation is worse, you need to re-download it at best or create a new VHD and re-install a system at worst.

I'm a little Leery about changing or recreating anything. I don't want to go through the hassle of calling MS to get the VM activated again. The first time was bad enough.

Slavic · Jan 4, 2022

Winuser said:
I'm a little Leery about changing or recreating anything. I don't want to go through the hassle of calling MS to get the VM activated again. The first time was bad enough.

I understand this problem. On my side, I used only non-activated VMs (with evaluation keys) because it was enough for tests, and even after evaluation time with all /rearm ended, VM could be created again as eval version. Of course, all applications had to be reinstalled. But I haven't used VM as a permanent environment and never had the "heavy" or activated products inside. Some people may have, though.

In your case the activation state should be saved in VHD in Registry and if you restore the parameters of previous VM, hardware configuration will be the same, so activation shouldn't be lost. Well, you may make a backup copy of VHD if something goes wrong.

Winuser · Jan 4, 2022

Slavic said:
I understand this problem. On my side, I used only non-activated VMs (with evaluation keys) because it was enough for tests, and even after evaluation time with all /rearm ended, VM could be created again as eval version. Of course, all applications had to be reinstalled. But I haven't used VM as a permanent environment and never had the "heavy" or activated products inside. Some people may have, though.

In your case the activation state should be saved in VHD in Registry and if you restore the parameters of previous VM, hardware configuration will be the same, so activation shouldn't be lost. Well, you may make a backup copy of VHD if something goes wrong.

I think the problem is with Hyper-V. I'm thinking a file got corrupted or a setting got changed. As a test I tried to make a new VM and it didn't work. I think my next step is trying a repair install. If that doesn't work, I can use my restore images to hopefully find out when it stopped working.

Bree · Jan 4, 2022

Winuser said:
As a test I tried to make a new VM and it didn't work. I think my next step is trying a repair install.

There is a much simpler fix for a 'broken' Hyper-V. Simply got to Windows Features and turn off Hyper-V. Then go back and turn it on again. This reinstalls Hyper-V and keeps all your existing VMs and their settings. The only thing you may need to set up again are any Virtual switches you may have added yourself, but if all your VMs use the Default Switch then that wouldn't be an issue.

cereberus · Jan 4, 2022

Slavic said:
I understand this problem. On my side, I used only non-activated VMs (with evaluation keys) because it was enough for tests, and even after evaluation time with all /rearm ended, VM could be created again as eval version. Of course, all applications had to be reinstalled. But I haven't used VM as a permanent environment and never had the "heavy" or activated products inside. Some people may have, though.

In your case the activation state should be saved in VHD in Registry and if you restore the parameters of previous VM, hardware configuration will be the same, so activation shouldn't be lost. Well, you may make a backup copy of VHD if something goes wrong.

This is not how it works. Any virtual machine has an vmid which is essentially the same as a physical pcs mobo id (call it virtual mobo id if you like).

This virtual mobo id is stored on MS activation servers in same way as any physical mobo id.

When you use vm export and later import it, you have option to keep original id or create new one (need a new key to activate).

The virtual mobo id is stored somehow with the virtual machine files, NOT within the registry of a vhd.

You can prove this by restoring the vm (with same id), clean install W10 on a blank vhd, and vm will activate automatically provided you install same edition, even without entering a key.

It is important (imo essential) to back up the vm configuration files somewhere else, in case you accidentally delete the vm from the hyper-v gui. Whether you back up the vhds is a matter of choice (provided you back up important data of course).

Winuser · Jan 4, 2022

cereberus said:
This is not how it works. Any virtual machine has an vmid which is essentially the same as a physical pcs mobo id (call it virtual mobo id if you like).

This virtual mobo id is stored on MS activation servers in same way as any physical mobo id.

When you use vm export and later import it, you have option to keep original id or create new one (need a new key to activate).

The virtual mobo id is stored somehow with the virtual machine files, NOT within the registry of a vhd.

You can prove this by restoring the vm (with same id), clean install W10 on a blank vhd, and vm will activate automatically provided you install same edition, even without entering a key.

It is important (imo essential) to back up the vm configuration files somewhere else, in case you accidentally delete the vm from the hyper-v gui. Whether you back up the vhds is a matter of choice (provided you back up important data of course).

With all of my trial and errors I did I decided to use a system restore I made on the 14th. I'm back to the Synthetic SCSI Controller error. I don't think it's a problem with the VM. I think it's either a setting was changed or a problem with Hyper-V.

Slavic · Jan 4, 2022

cereberus said:
You can prove this by restoring the vm (with same id), clean install W10 on a blank vhd, and vm will activate automatically provided you install same edition, even without entering a key.

You mean that the activated VM gets a digital licence which is bound to "hardware" configuration the similar way like on real PC hardware. As a result, the key is no longer needed, and some small changes in config will not reset the activation. Yes, I thought that it is stored somewhere in internal VM configuration in Registry, but you said (I think it's a direct info from devs or a result of tests) that specifically in VM activation is stored outside of VHD, but is still available from inside (otherwise Windows will not be able to determine its activation state). While I never worked yet with activated VMs, it's an important info. Thanks!

cereberus · Jan 4, 2022

Winuser said:
With all of my trial and errors I did I decided to use a system restore I made on the 14th. I'm back to the Synthetic SCSI Controller error. I don't think it's a problem with the VM. I think it's either a setting was changed or a problem with Hyper-V.

Post these images from settings menus and folders. I suspect something in settings is pointing to wrong place.

Also show where the iso is.

Winuser · Jan 4, 2022

When I get back on my desktop, I'll try to get the info you asked for. If needed do you know how I can reinstall Windows 10 and keep my activation? Hyper-V is new to me, so it won't take much to get me lost. Seems like every time I try to learn about Hyper-V I mess up. I feel more comfortable using the free VMWare Player.

Mystere · Jan 4, 2022

Winuser said:
That was my first thought. The file is right where it should be. I can't even import the saved VM. I'm thinking a setting got turned off.

View attachment 17488
View attachment 17489

There is no "Virtual Machines" directory in the screen shot you posted.

cereberus · Jan 4, 2022

Mystere said:
There is no "Virtual Machines" directory in the screen shot you posted.

Yeah - not sure why op is trying to import a vm. I am presuming there is a folder ....\windows 10 pro\virtual machines

Winuser · Jan 4, 2022

I want to thank everyone for trying to help me. I managed to import the Windows 10 VM. I decided that I wasn't going to worry about losing the activation and deled the VM. After that I was able to import the VM. I'm still getting the Virtual SCSI Controller fails to start error.

Winuser · Jan 4, 2022

@cereberus, here are the images.

Solved Hyper-V error

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