To reduce the disk size for Windows Server 2012 virtual machine:
1. In the Computer Management section, select Disk Management. Right-click on the necessary logical volume and select "Shrink Volume ...". Reduce the volume with a small margin following the instructions in the wizard.
2. In the Cloud Control Panel, add a disk for the system image backup, format and assign a letter to the new logical volume in operating system. If necessary, install Windows Server Backup System component and perform a backup using the wbadmin command, similar to the figure.
3. Turn off the machine. Remove the scratch disk. Add a system recovery disk from an image. Mount Windows Server distribution and turn on the machine, at the first step "Windows Setup" click "Next", at the second step - "Repair your computer".
4. In the window that appears, select "Troubleshoot", in the next "System Image Recovery", then use the wizard to restore the system.
5. Turn off the machine and remove the system image disk. Extend system volume to an unallocated area of the scratch disk.
