Assuming that you might have genuine reasons to use the system drive as the default location for the virtual machines, the bitter truth is that you cannot reduce the size of the snapshots of the virtual machines. As the size of the operating system files grows, the overall size of the captured snapshots grows in the same proportion.
The only remedy for this kind of issue is to change the default snapshot location. When you change the default location for the snapshots, the snapshots are no longer saved in the system drive, hence leaving the space of the drive unused.
Here is how you can change the default location where the Windows Server 2012 Hyper-V server saves the snapshots of the virtual machines:
- Using the appropriate account that has the required privileges, log on to the Windows Server 2012 computer on which the Hyper-V role is installed.
- If not already started, initialize the Server Manager window from the bottom left corner of the screen.
- Once the Server Manager window is initialized, from the left pane, click to select the Hyper-V category.
- From the right pane, under the SERVERS section, right-click the Hyper-V server from the available list.
- From the context menu that appears, click the Hyper-V Manager option.
- On the opened Hyper-V Manager snap-in, from the left pane, right-click the name of the
server. (DC-01 for this demonstration.).
- From the context menu, make sure that the service is started and all the contextual options are visible. If the service is not started, you must click the Start Service option from the context menu, and then right-click the server name again and continue with the instructions.
- From the center pane, click to select and then right-click the virtual machine on which you want
to mount the bootable ISO image to install the required operating system.
- From the context menu, click Settings.
- From the opened box, from the left pane, under the Management section, click to select
the Snapshot File Location category.
- From the right pane, click the Browse button.
- From the opened Select Folder box, browse and locate the drive or folder where you want to save the captured snapshots of the virtual machines.
- Once the target location is selected, click the Select Folder button to confirm the location.
- Back on the virtual machine settings box, click OK to save the changes that you have made.