In Windows it is possible to create a virtual hard disk (vhd, vhdx) by standard means or mount an existing one.
Press Win + R, enter compmgmt.msc, in the window that opens, do the following:
Next, select the path to save the new disk, the format and type of the virtual disk, fixed or dynamic.
Fixed is a common type of disk, and if we give it, for example, the size of 50GB, then a 50GB xxx.vhd file will be created, immediately reserving all its space for ourselves.
If you select the dynamic type and specify the same 50 GB, then a file with a size of only a few tens of kilobytes will be created. And when copying files to such a disk, the size of its file will accordingly increase and decrease when deleted, that is, its size will always be approximately equal to the total size of the files on it. In Explorer, the size of the disk will always be listed as 50 GB. Due to this specifics of work, the speed of the disk may be lower than that of the fixed type.
After confirmation and creation, a new virtual disk will appear in the window - " Disk 1 ".
To make the disk available for use, you need to perform the same operations with it as when adding a regular new hard disk to the computer, that is, initialize and create the partition (s).
See Adding a new hard drive to your computer .
After restarting Windows, the virtual disk will disappear from the system. You can connect it back with the usual double-click on the disk file.
To connect the drive automatically at system startup, you can put it in startup. To do this, you need to create a shortcut to the disk file by selecting the appropriate item in its context menu. Press Win + R, enter:
%PROGRAMDATA%\Microsoft\Windows\Start Menu\Programs\StartUp
and move the shortcut to the opened folder.