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Diskpart does not Extend or Expand Windows Server 2003 C: Boot Partition

May 10, 2009

I recently had a customer contact me about a Windows Server 2003 VMware virtual machine that was running out of disk space.  The customer increased the size of the .vmdk file by editing the virtual machine settings, then rescanned the disk using Disk Manager inside the guest OS to verify that the additional un-partitioned space was available.  When the customer attempted to run the diskpart utility to extend the boot partition, he encountered the error message “Diskpart failed to extend the volume. Please make sure the volume is valid for extending” .  Microsoft Knowledge Base Article 325590 How to extend a data volume in Windows Server 2003, in Windows XP, in Windows 2000, and in Windows Server 2008 states, “Only the extension of data volumes is supported. System or boot volumes may be blocked from being extended, and you may receive the following error: Diskpart failed to extend the volume. Please make sure the volume is valid for extending”.

There are several different ways in which you can extend the boot partition of the Windows Server 2003 virtual machine.  Pete Cheslock shows you how to present the virtual machine’s .vmdk file to a second Windows Server 2003 virtual machine and extend the partition there in his article How to Extend Windows Boot Volumes in VMware.  Andrew Lambert wrote an excellent post on Resizing and Adding Partitions using Gparted Live.  At VMware Education we use the DELL Basic Disk Expansion Tool v.1.0.4, A01 also known as EXTPART.  It is by far the quickest method to extending the boot partition of a Windows Server 2003 virtual machine online.

I have used this tool extensively in production environments and have run into a few challenges I wanted to share.

The space used for expansion must be contiguous free space.  For example I had a customer who created two partitions on Disk 0; the first partition was the C:\ (boot), and the second partition was the D:\ for the pagefile.sys.  When the customer ran out of disk space on the C:\ (boot) partition they were unable to extend because the D:\ was “in the way”.

Unable to connect to C: or it does not exist.  This error message seems to appear if you have the File Replication service or Symantic Endpoint Protection running on the server, stop both services if they are running and EXTPART will execute.

Does it work for x64 Systems? Yes.  This question comes up quite a bit, the self-extracting zip file from Dell won’t run on 64-bit. Simply rename it to, then copy the extpart.exe out of the archive, I usually put it at the root of C:\

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