Diskpart - "The volume you have selected may not be extended" on Windows 2003 Server when enlarging boot disk (C:) in VMware ESX 3.5
This solution may apply to anyone trying to extend a primary boot volume in Windows 2003 Server (mine happened to be the R2 Enterprise edition, but may apply to prior versions of 2003 Server). I was following VMware KB 1007266 to extend the boot volume on this Windows 2003 guest VM on ESXi (3.5). This is a separate issue from the Microsoft KB # 841650 . Everything was fine when I attached the newly extended VMDK file to my helper VM. But I kept getting the "The volume you have selected may not be extended" error and couldn't figure out why. It turns out I didn't read the KB carefully enough. Make sure you assign a drive letter in the Windows Disk Management UI first! Before assigning a drive letter: DISKPART> list disk Disk ### Status Size Free Dyn Gpt -------- ---------- ------- ------- --- --- Disk 0 ...