VM Failing to Reboot

kagbasi-ngc

@nathanael-h So I just used the xenbootfix.exe to clean out the guest tools/drivers, however, that hasn't helped. At least now the boot process is failing to a BSOD, but what's interesting is that I get a different stop code.

I have a snapshot that I can revert to and start over, but I really don't want to (if there's any chance of fixing this).

BSOD (after a normal startup

BSOD (after a recovery startup):

nathanael-h

@kagbasi-ngc it looks like the same issue you had in https://xcp-ng.org/forum/topic/10140/bsod-with-inaccessible-boot-device-after-uninstalling-the-xcp-ng-guest-tools/ is the solution suggested by @dinhngtu works here?

kagbasi-ngc

@nathanael-h Yes it seems so, except that this time I’m unable to boot successfully into Windows.

dinhngtu

@kagbasi-ngc Can you attach a kernel debugger using the VM's serial console?

kagbasi-ngc

@dinhngtu Ooo, sounds interesting. Not sure how I would do that, but certainly open to learning.

dinhngtu

@kagbasi-ngc You'll find the instructions here: https://github.com/xcp-ng/xcp-ng-org/blob/wintools/docs/troubleshooting/windows-pv-tools.md#connecting-to-guests-using-serial-console

kagbasi-ngc

@dinhngtu Thanks. I read through the instructions, and given that I'm unable to boot into Windows, I don't think I'll be able to complete this step:

To configure kernel debugging on Windows, disable Secure Boot and BitLocker then run the following commands within the VM:
bcdedit /debug on
bcdedit /dbgsettings serial debugport:1 baudrate:115200

Is there an alternative?

dinhngtu

@kagbasi-ngc You should be able to get into debugging mode via the Advanced Boot Options menu (spam F8 at boot). You'll still need to enable Secure Boot. I'm not sure if you'll be able to connect without running the /dbgsettings command, but it's worth a try. Note that you'll need to have WinDbg ready and connect it as soon as you select debugging mode.

If all that fails, can you use Safe Mode or Last Known Good Configuration?

kagbasi-ngc

@dinhngtu Okay, gonna give it a shot now. Will report back shortly.

kagbasi-ngc

@dinhngtu Unfortunately, no amount of smashing of the F8 key got me into the Advanced Boot Options menu, so I gave up on that.

Instead, I've booted up with Hiren's Boot Disc, and I'm about to see if perhaps I can uninstall the guest tools this way and try again. Any pointers are welcome.

dinhngtu

@kagbasi-ngc You can enable debugging from within Hiren's by mounting the Windows EFI system partition to e.g. S: then running bcdedit /store S:\EFI\Microsoft\Boot\BCD /debug on

You can also try renaming the .sys files but normally XenBootFix should have been sufficient to disable all Xen drivers.

I forgot to ask, how did you install guest tools onto your VM, and did you install anything else to it (e.g. some 3rd-party apps) before rebooting?

kagbasi-ngc

@dinhngtu I installed the Citrix Tools into my template and then built the VM from the template (as I've always done). However, immediately prior to the reboot, I had just finished installing MediaEnable (email server) and was just trying to reboot to get some Group Policies to take effect.

Prior to that, I'd already rebooted the VM many times and not had any issues, however, I was always rebooting using the buttons in XOA not directly from within the OS.

I'm gonna go try what you've suggested now and see what happens.

dinhngtu

@kagbasi-ngc Is it possible that your GPOs or MediaEnable that are causing the BSOD? Could you try to eliminate the causes?

kagbasi-ngc

@dinhngtu Sure, it's possible - though not likely. However, I'm willing to entertain you and I would uninstall them, except that I can't boot into the OS.

Anyway, I tried what you suggested by attempting to enable BCD Debug and it didn't work - got an error (even though the path is correct) :

dinhngtu

@kagbasi-ngc It's not the BCD database path but the BCD entry identifier. Try bcdedit /store ...\BCD /enum to get the entry's identifier, then bcdedit /store ...\BCD /set <identifier> /debug on

dinhngtu

Also, one way to verify the issue is to install MediaEnable on another VM.

kagbasi-ngc

@dinhngtu Thanks, I did that but getting an error message that The system cannot find the file specified

dinhngtu

@kagbasi-ngc There's no slash in debug while using the /set command:

Also please don't enable debugging for bootmgr, just do it on {default}

kagbasi-ngc

@dinhngtu said in VM Failing to Reboot:

@kagbasi-ngc There's no slash in debug while using the /set command:

I had already tried that, but I think I did it on {bootmgr} - so I'll retry on {default} when I get back in the lab.

Update as of 09:58AM EDT:
I tried the command against the {default} identifier, and it worked. However, I didn't see any change in behavior during the boot process. Should I continue with the instructions for exposing the VMs serial console?

kagbasi-ngc

@dinhngtu said in VM Failing to Reboot:

Also, one way to verify the issue is to install MediaEnable on another VM.

So, I built a new VM from the same template, renamed it and joined it to the domain (both actions required a reboot which was initiated from inside the OS). I then placed it in the correct OU and rebooted so it will grab the correct GPOs (this reboot action was also initiated from inside the OS). Finally, I installed MailEnable and when it finished I initiated a final reboot from inside the OS.

None of the reboots caused the OS to fail to boot, and it was built from the same template (which has the Citrix Guest Tools v9.4 installed). Below is a link to a video I took of the test.

https://photos.app.goo.gl/Uw7WgFRY1BEem8gA8