Computers and Internet

Error Code: 0xc0000034 in Windows Server 2012 R2 using Dynamic Boot Disks

I spent good part of the weekend away from kids dealing with this issue and with hopes to save another dad from the same trouble, I’m posting my experience.


You have a server (Windows Server 2012 R2) or desktop (Windows 8.1) with software Raid1 to handle boot drive. Due to various failures (root cause not much relevant), you find yourself with the error 0xc0000034 and failing to boot from either of these disks (plexes).

There are bunch of posts on the Internet about this, mostly centric around bootrec /rebuildbcd – problem is, dynamic disks are different. Here how I was able to recover:

1. First, don’t assume both plexes of the mirror contained the same information at the time of failure. In my case, I had been swapping one plex after another, trying these commands. I would get “foreign disk” in diskpart, which of course prevents any kind of recovery action. Lesson: Keep BOTH plexes / disks plugged into the system during recovery efforts; in my case, only having both allowed me to proceed to next step.

2. Boot with Windows Server 2012 R2 RTM installation media, choose Repair, then Troubleshooting and then choose Command line. From there, go to diskpart and make sure the partition (NOT volume, even though you might think dynamic disk has less to do with partitions) that contains the OS is set ACTIVE. Without this, bootrec /scanos does not find any OS and cannot do any BCD rebuilds.

  • – list disk
  • – select disk X
  • – list partition
  • – select partition X (where X is the partition containing the OS volume)
  • – active

3. Once you set it active, proceed to with bootrec /rebuildbcd and then OS restarts from there.

4. At that point you need to ensure mirrors are healthy and you can take backups of your files, continue with troubleshooting.

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