Follow the instructions below to exclude Hyper-V Virtual machines by excluding the VHD files in Server Backup Policy.
By default, all file(s)/folder(s) located on a Device are replicated.
2. Select the "File Excludes" tab.
3. Using the Backup Manager Web Interface, browse the files and folders on the Server's hard disk.
4. Select checkboxes next to the files and folders you want to exclude from the replication.
You can add rules to exclude files by pattern. For example, *.vhd. See Advanced Excludes in Exclude files and folders.
5. Click on "Save" or "Create" at the bottom of the window.
The selected files and folders will be ignored by the Policy. Files and folders that are not selected will be considered by the Policy.
Read more in Exclude files and folders.