Force Windows to recalculate disk size on VM after resizing hard drive

Question

Is there a command line or similar that I can run to force Windows to recalculate disk size on a VM after resizing the hard drive?

Solution

Yes there is!

1. Start CMD in an elevated prompt
2. Run 'diskpart'
3. Run 'Rescan Devices'
4. Run LIST VOLUMES to get the list of volumes
5. Run SELECT VOLUME #, where # is the number of the volume needing expansion
6. Run EXTEND to expand the volume into the newly visible free space

We use this procedure for volume extensions on physical servers as well, when the volumes are on a SAN.

Comments

[Dustin Kendall]

Thank you. This worked for me. I only had to change EXPAND to EXTEND and it worked like a charm.

[Deb]

One of the two, and I always seem to guess wrong! Thanks.

[Aashraya Singal]

BTW on 2008 or Win7, you can do it all from Disk Management - There's an 'extend' option on the context menu for the partition, after you've rescanned. Also, on 2008 and Win7, you can do this on boot volumes. On versions prior, you need to use a GParted LiveCD to resize the partition.

[Dustin Kendall]

That's good to know Chris, thanks. For my particular case I need to script this so this answer was just what I needed.