Fixing a RAID1 that suddenly becomes write protected (64 bit Windows)

Lars Erik Jordet — Thu, 14 May 2009 17:34:34 +0000

Today, after rebooting from some Windows updates, my RAID1 disk suddenly was write protected – but a way to change it was nowhere to be found. After some digging, I found that others have reported the same problem.

Background

As far as I can tell, it seems to be a weakness in the 64-bit drivers for the on-board RAID on some motherboards that causes it. For the record, mine is a Gigabyte GA-EP45-UD3P, and I’m running Windows 7 RC (7100) 64bit, but it seems to be reported for all 64 bit versions of Windows. Anyhow, the fix itself is simple, and seems to stick over reboots, and hopefully it’s permanently fixed.

Fixing the problem

To solve the problem, we need to open an elevated command prompt; in both Windows 7 and Vista, you do this easily by hitting the Windows button, typing “cmd”, right-clicking the “C:\ cmd” search result, and selecting “Run as administrator”. In Windows 7 you can also find Command Prompt in the Start menu and Ctrl-Shift-click it, to open it elevated.

(Disclaimer: The DISKPART tool can potentially remove/create partitions on your hard drive, so be 100% certain what you’re doing before you hit Enter)

In the elevated Command Prompt, type “diskpart” and press enter:

1	C:\> diskpart

On the diskpart prompt, list your volumes:

1	DISKPART> list volume

In my case, the volume on my RAID was volume 4, so I selected it:

1	DISKPART> select volume 4

…and then I marked it writeable like this:

1	DISKPART> attributes volume clear readonly

Here’s the entire segment in a screenshot (note that I did a couple of extra steps selecting the disk, this is apparently not necessary):

DISKPART commands for removing read-only

Saved for later reference » raid

Fixing a RAID1 that suddenly becomes write protected (64 bit Windows)

Background

Fixing the problem