I needed to extend the main storage of my fileserver this morning. While VMware happily extended the storage volume for the VM when I asked it to, Windows 2012 R2 was not so helpful. Luckily this is easily fixed.
In Disk Manager (diskmgmt.msc) make sure the disk to be extended is set to be “Dynamic”. If it is, simply Re-scan the disks. Now it can be extended just fine. Screenshots below:
Error when extending disk:
Disk extended to use the extra space: