Just got a spanky new VM for my squirrel server and the sysadmin took off for the holiday and left the drives offline.
Disk Management for whatever reason was no help, even running as Administrator. The disks were flagged as readonly by policy and would not online or initialize via the GUI tool.
So break out the cmd window and get to DISKPARTying
DISKPART
select disk #
online disk
detail disk
attribute disk clear readonly
detail disk
Now can close and reopen Disk Management (diskmgmt.msc) and it can now initialize the disks 🙂
http://support.microsoft.com/kb/971436