In the past, I haven't had problems running UniServer from whatever USB Drive I've installed it on. That is until recently. When attempting to run UniServer on any of the computers in my home network, I get the message that drive w is busy, even when I know that I haven't mapped the drive. The mystery is this, on both of the two systems, I can create a synchonized copy of the entire site (using Window's "Briefcase") or run UniServer "Stand Alone" on either computer, UniServer runs fine. To further deepen the mystery, when I go to school (college) and run UniServer off the same USB Drive that "fails" at home, the server is "pleased as punch" to run on the USB Drive as it was intended. I have seen circumstances where another server, especially if its an Apache server is already running, where UniServer will not run. However, I'm at a loss as to why on the very same computer, with no other change than moving it from the USB drive to the fixed disk, its able to run one place (on the hard drive) and not the other. As I have posed this question I may have answered my own question; but, I do want more input in regards to this difficulty. It has occurred to me if I haven't given the (on the USB Drive) Server & mySQL permission to run by either my Firewall or AntiVirus, that it could account for my being able to run it "one place" and not the "other". In a related question, I notice that the start up of UniServer creates a "virtual drive" using the DOS SUBST Command. Is it possible to allow it to run off a networked drive?