Installing Windows on an old unRAID drive.

By | August 19, 2012

I thought I would share this since it caused me to scratch my head a bit.  I had to use a 1TB drive from a spare system of mine as an unRAID replacement after a drive failure last week.  Well, that system was my decommissioned desktop and I still used it to do encoding and other heavy work as I relocated it to the basement.  I just remote into it now.  Anyway, I found a couple of 500GB drives that were taken out of my unRAID server some time ago due to upgrades, so I went to use one of those as a new OS drive…except none of them were found during the disk selection phase.

No drives

No drives

I tried three different drives, all 500GB taken from my unRAID server for larger drive upgrades.  They were all seen at boot time by the BIOS and controller scans, but were absent when it came to the disk selection portion of the Windows 7 install procedure.  I knew this was not a case to load an external driver, an issue with AHCI, or anything like that.  I had just installed Win7 on this same system a couple of weeks before.  It wasn’t until I decided to go to the repair console command line from the System Recovery screen that I finally got a hint as to what was going on.  I don’t remember exactly what it was that I tried, but I received a reply that indicated an unknown file system or corrupted volume information.  It was then I realized that unRAID must have written something to the drive causing Windows to say, “WTFISTHISDISKDRIVEFAIL”.

Fine.  The next thing I did was to run DISKPART to launch the disk partition utility so that I could make something out of this drive that the install disk could use.  Once at the diskpart command, I ran LIST DISK.  You will get something similar to the below image (I ran this from my laptop, post de facto, so some info will be different).

list disk


All we’re really interested in there is the DISK ###, which indicates the disk ID.  In this case, it is 0 (zer0).  Next, we want to select this disk, so I ran


You’ll get a reply that, Disk 0 is now the selected disk.”   Good.  The next thing is clear any read-only flags that may exist.  There’s no reason for this other than to be thorough and avoid any stroke-inducing frustration later if you do have a read-only flag set on something somewhere.


That will be followed by a, “Disk attributes cleared successfully.” message.  Again, good.  Now, let’s clean the disk.


When all goes well there, it will return, “DiskPart succeeded in cleaning the disk.”  It’s time to create our master boot record.


That will result in, “DiskPart successfully converted the selected disk to MBR format.”  Yay!  One more step to go.


After receiving the message, “DiskPart succeeded in creating the specified partition.“, we can simply type EXIT to quit the diskpart utility.  just reboot the system, begin the installation procedure again, and the drive will be available when reaching the drive selection phase.  From there you will see the drive in its entirety as we created the one large partition.  However, you can do whatever you want with it at that point using the advanced options.

Hope this helps someone avoid some headaches!

2 thoughts on “Installing Windows on an old unRAID drive.

    1. Jon Post author

      Probably easier to just drop the drive in a working Windows system and let the Disk Management MMC do all that for you, but that was actually the less convenient method for me at the time :)


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