Extend System Volume Error ‘The parameter is incorrect’

I had an issue when extending the volume of a Windows Server 2008 system drive where it returned the horrible looking error below ‘The parameter is incorrect’.

DiskGrowParameterIncorrect

This leaves you in a scenario where the Disk Management tool reports that the disk has been increased to the new size, but viewing the disk properties in Explorer shows it has not been increased.

DiskSizeMisMatch1

It turns out this has been an issue within Windows Server for sometime and this Microsoft KB article details how to resolve it with the Diskpart utility, essentially the disk partition has been increased, but not the file system size.

It’s as simple as

DISKPART

DISKPART> select volume #

where # is the number of the affected volume which can be found with list volume.

DISKPART> extend filesystem

Now the file system size should match the new partition size.