Why does InStat give me the message "This copy of InStat is for a single user, and is already in use"?

With a single-user license for InStat, you must launch it from a hard drive on your own computer. InStat will not launch from another drive on your network, unless you install it under a network license.

This message will also come up from InStat Mac, if it detects that your InStat serial number is already in use on another computer on the network. If you have a single-use license, InStat Mac won't begin if that license is in use elsewhere on the network.