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Was doing routine updates and one of our Windows Server 2019 hypervisors didn't come back up afterwards. Instead it gives the error "INACCESSIBLE BOOT DEVICE".

I've followed various guides to rebuild BCD, fix MBR (even though it's GPT and as I understand it MBR is not used?), removed updates with DISM. I've run chkdsk /f /r, I've run sfc /scannow and I've even tried to restore the registry from the RegBack directory.

I'm reluctant to give in and rebuild this server for a couple of reasons:

  • Our DR isn't the best. We have backups of the VMs but not the server config. This is purely because we don't have the capacity to back up the hosts as well as the VMs and I can't get the budget to order an additional tape drive.
  • This is our backup server so I would need to find a server with resources (unlikely) and configure it with the tape drive so that I can use it to restore.

I'm ont sure how relevant it is, but when listing volumes in diskpart, the C: drive doesn't say "boot" in the info column, which sounds wrong to me. enter image description here

Additionally when running bootrec /fixboot I get an access denied error. I've followed various guides but I can't find a solution that works for this server, they all suggest rebuilding the EFI which I've already done.

Does anyone have any suggestions for me to repair this server? It looks like all the data is there on the C: drive but it just can't boot from it. Please help!

Edit-

I've found now that in bcdedit, the device parameter is set to partition=\Device\HarddiskVolume2. I think that this should instead be set to the EFI volume, which I would assume to be partition=\Device\HarddiskVolume1 as it's volume 1 in diskpart. Attempting to set this with bcdedit /set {bootmgr} device partition=\Device\HarddiskVolume1 system partition returns an error saying the file specified cannot be found. Am I correct in my assumptions that this device is incorrect? If so, how can I set it correctly?

ryansin
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  • If you boot with EFI, no partition needs to have the bootable flag. Rather, the system boots using files in the EFI partition. – Michael Hampton Sep 13 '20 at 15:12
  • @MichaelHampton Thanks so much, that clears that up. So I've found now that in `bcdedit`, the `device` parameter is set to `partition=\Device\HarddiskVolume2`. I think that this should instead be set to the EFI volume, which I would assume to be `partition=\Device\HarddiskVolume1` as it's volume 1 in diskpart. Attempting to set this with `bcdedit /set {bootmgr} device partition=\Device\HarddiskVolume1 system partition` returns an error saying the file specified cannot be found. Any thoughts? – ryansin Sep 13 '20 at 15:27
  • Looks like volume 0 to me, not 1. But it's been quite a while since I had to repair a not-booting Windows installation. – Michael Hampton Sep 13 '20 at 15:29
  • Why are you not backing up the Hyper-V host? This would be relatively simple to do with Windows Server Backup (free) or Veeam Agent for Windows (free) and you could back up the host to an externally attached USB drive. Veeam Agent for Windows has a tool to create recovery media that in a DR scenario you'd simply boot the Hyper-V host to the recovery media and restore the host from the backup on the external USB drive. – joeqwerty Sep 13 '20 at 15:53
  • It's a valid question @joeqwerty, the tape drive is on 24/7 at the mo. We simply don't have the capacity to back up hosts. – ryansin Sep 13 '20 at 15:58
  • @MichaelHampton the C: drive is volume 0, but the EFI bootloader is what the BCD bootmgr needs to point to. – ryansin Sep 13 '20 at 15:59
  • What I'm suggesting is that you don't backup the hosts to your tape drive. That creates a circular dependency. Back up the hosts to externally attached USB drives. I use Veeam Agent for Windows to backup my Hyper-V host and the backup size is all of 50 GB. – joeqwerty Sep 13 '20 at 16:02
  • Thanks @joeqwerty I will consider that going forwards – ryansin Sep 13 '20 at 16:26
  • @ryansin The BIOS loads the EFI bootloader, which then loads Windows off the Windows partition (or the Bitlocker partition, which you don't seem to have), not the EFI partition. – Michael Hampton Sep 13 '20 at 16:33

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