No idea what you mean by a reserved file. I would suggest you use all drives the the OS advertises. If you are bypassing the OS for file access that is a concern. Mapping X: to C:\ doesn’t make much sense to me. I’m trying to avoid mounting my entire C: drive on the remote machine. Seems dangerous.
But you can close this question. I discovered drag and drop.
Going forward, I recommend allowing me to drop places other than the desktop. Also, allow a windows explorer-like interface similar to, but better than VNC’s.