Remote Desktop Services (previously known as Terminal Services) now has the option of using ‘User Profile Disks’ for each user (essentially a mini VHD containing their profile). Whilst this is a great idea (and works well), the default size is quite small and cannot be changed once set…
To increase the size for existing users (have to repeat for each!) you must ensure they are not logged on and then:
1. Identify which VHDX belongs to which user by running SIDDER (note run as admin!)
2. Log on to Hyper-V host and launch Hyper-V Manager, select Edit Disk, browse to the shared location and select the identified VHDX.
3. Run through the wizard, use expand disk and adjust size to suit.
4. Launch Disk Management, browse in Windows Explorer to VHDX file and Mount.
5. Select drive in Disk Management window and Extend Volume to desired size.
6. Eject drive.