If your Hyper-V Virtual Machine run out of virtual disk space, you can add and expand the disk as long as you have enough physical space available.
2. Now, power down the Virtual machine so that it state is “off” in the Hyper-V Manager. After that, highlight the Virtual Machine and then click “Edit Disk…” under “Action” on the right.
3. A Edit Virtual Hard Disk Wizard window will pop-up on the screen. To continue, simple click the “Next” button.
6. In the next screen, you can choose 4 different actions you can do to the virtual disk. In this example, we go with “Expand”. Click “Next” to continue.
7. Now, enter the new disk size you like you virtual disk to be expanded to. In this example, I enter “120GB” in the text box provided and click “Next”.
9. Once that is done, you can start/power on the virtual machine follow by “Connect…” to the Virtual Machine console.
10. Open the Windows 8 or Windows Server 2012 search page and type computer. Once the Computer app appears on the left, right click the “Computer” and choose “Manage” at the bottom.
11. In the “Computer Management” screen, choose “Disk Management” under “Storage”. You should see the additional space listed on the screen now as Unallocated space.
13. A Windows Extend Volume Wizard will pop-up to guide you through the drive expansion process. Click “Next” to begin.
14. Select the disk you like to expand and choose the amount of space you like to expand. Once that is done, click “Next”.
16. At this point, you should see the new size of the virtual disk inside the Disk Management screen.