How do I create a drive for only one user (session)?

To create a virtual drive for only one user, include the STGMP_LOCAL flag—in addition to the STGMP_SIMPLE or STGMP_NETWORK flag— when calling the AddMountingPoint method. If you need to create a mounting point for a user session other than the current one, you'll also need to supply the Authentication ID that corresponds with that session using the AuthenticationId method parameter. Refer to the documentation for more information.