[PVE-User] win 2012 | resize disk, new size not seen from windows

[mj]

Hi,

Running a win2012 guest on proxmox 5.3 with ceph storage backend. The 
disks are added as scsi0 and scsi1. I have enlarged scsi1 (the data 
disk, non-boot device) using the proxmox gui from 900GB to 1800GB.

I have shutdown/restartd the win2012 guest, but it's Disk Management is 
not recognising the new disk size. I have refreshed and rescanned: no 
change. No empty space at the end of the device is showing up and extend 
Volume is greyed out.

Am I missing a step somewhere..?

MJ