Hi experts

When I try to boot my uefi client from LAN it successfully downloads boot.wim from my WDS 2012, shows the Windows Logo for some seconds, but then it crashes, showing BSOD and the message "UNMOUNTABLE_BOOT_VOLUME".

I'm using the same x64 boot.wim as with the BIOS clients, but with the mbr clients it works.

What is it, that makes my boot.wim unusable for uefi clients?

• Edited by woodrapp Monday, June 08, 2015 1:15 PM

Ok the PE should be 5.0. The first thing I would recommend is make a bootable CD or USB with that boot.wim and see if you can do a UEFI Boot that way.

I have seen this message before on older WDS and WinPE and it was caused by a network issue. That might be what is happening here and if so it is difficult to troubleshoot.

• Proposed as answer by Kate LiMicrosoft contingent staff, Moderator Monday, June 15, 2015 12:13 PM
• Unproposed as answer by woodrapp Monday, June 15, 2015 12:49 PM

Ok the PE should be 5.0. The first thing I would recommend is make a bootable CD or USB with that boot.wim and see if you can do a UEFI Boot that way.

I have seen this message before on older WDS and WinPE and it was caused by a network issue. That might be what is happening here and if so it is difficult to troubleshoot.

• Proposed as answer by Kate LiMicrosoft contingent staff, Moderator 19 hours 2 minutes ago
• Unproposed as answer by woodrapp 18 hours 26 minutes ago

I always use the system's boot menu and manually select the UEFI option just to be sure.

If you are doing a PXE boot, usually the screen changes aka text/screen area becomes smaller than if you do a legacy boot.

• Proposed as answer by Kate LiMicrosoft contingent staff, Moderator 19 hours 2 minutes ago
• Unproposed as answer by woodrapp 18 hours 26 minutes ago

I always use the system's boot menu and manually select the UEFI option just to be sure.

If you are doing a PXE boot, usually the screen changes aka text/screen area becomes smaller than if you do a legacy boot.

• Proposed as answer by Kate LiMicrosoft contingent staff, Moderator Monday, June 15, 2015 12:13 PM
• Unproposed as answer by woodrapp Monday, June 15, 2015 12:49 PM

I tried the following:
I made a WinPE bootable USB-Stick with ADK 8.1, booted my PC from that stick in UEFI mode, and it worked.
Then I took the boot.wim from my WinPE Stick and loaded it as an additional boot image on WDS. When I pxe-boot my UEFI client from that boot.wim coming from adk, I get the unmountable_boot_volume error again.

Then I thought, maybe some drivers are missing, and I injected all the device drivers I could find into my boot.wim, but that would not make a difference.

• Edited by woodrapp Monday, June 15, 2015 12:56 PM

I checked the logs. There is nothing reported, except for a successful download of boot.wim.

I tried the following:
I made a WinPE bootable USB-Stick with ADK 8.1, booted my PC from that stick in UEFI mode, and it worked.
Then I took the boot.wim from my WinPE Stick and loaded it as an additional boot image on WDS. When I pxe-boot my UEFI client from that boot.wim coming from adk, I get the unmountable_boot_volume error again.

Then I thought, maybe some drivers are missing, and I injected all the device drivers I could find into my boot.wim, but that would not make a difference.

• Edited by woodrapp 18 hours 19 minutes ago

What is the make/model of the client? And are you only using a single device for testing or can you try your 64bit PE on other UEFI capable hardware? Also you might be able to use a Gen-2 Hyper-V VM if you have that installed on something.

Also, can you try a 32bit WinPE?

Drivers at that point aren't even loaded. The client is having trouble booting the image, well before any drivers you put in there are touched.

I still bet there is some network issue at hand. Take a look-see in the Event Viewer, under the WDS specific section called Deployment-Services-Diagnostics and see if there is a hint in there. I recommend attempting a PXE boot, so that it fails, then check the logs.

Desktop and Notebooks, different models, but always HP.

WinPE 32bit seems not to be bootable on uefi client.

edit: Meanwhile I installed MDT and created a Lite Touch Boot Image: same error (Unmountable_boot_volume)

• Edited by woodrapp 21 hours 53 minutes ago

Desktop and Notebooks, different models, but always HP.

WinPE 32bit seems not to be bootable on uefi client.

edit: Meanwhile I installed MDT and created a Lite Touch Boot Image: same error (Unmountable_boot_volume)

• Edited by woodrapp Thursday, June 18, 2015 9:30 AM

Hmm do you get any BIOS options on the HP? When doing UEFI testing (32 or 64bit) some system have different options and not everything works. For example, one system I have here has options like this:
- Windows 7
- Windows 8
- Windows 8 with CSM

In that case, "Windows 7" means legacy boot, "Windows 8" means UEFI and the CSM one means hybrid or both are enabled.

I use the one without CSM.
Do I need to inject some special secret driver into my boot.wim?

No, this message occurs before any drivers in the boot.wim are loaded.

Try the different BIOS options to see if any work.

I tried different BIOS options > no avail.

Could it be that there ist something wrong with the bcd-file generated by wds??

I do not know as I haven't experienced this exact problem, nor do I have access to that hardware in order to attempt to replicate.

But, in WDS do you have a boot image specified for the x64 UEFI response?