Situation:

Our C: drive on a test PVS image (Private mode acccess) was nearly full

We extended the vDisk following this process

1. Open Cmd Prompt
2. diskpart
3. Select vDisk file=”Path to your PVS vDisk”
4. List vDisk
5. expand vDisk maximum=xxxxx (in Mb) (61440 for 60GB etc)
6. attach vDisk
7. list Disk
8. list volume
9. Select volume x
10. extend
11. List volume
12. detach vDisk
13. exit

After detattching and booting the Test PVS Server windows wouldn’t boot with a System volume couldnt be accessed

Solution:

Repeat steps 3,6 and 12 to reattach the disk and deattach the vdisk cleanly then boot the VM.