Hi The license is tied to the MAC address of your network card. If you are not on a network, you need to get and use an offline license as well. So, if you have installed the software and gotten a license file from ptc.com, the next thing you need to make sure is that the MAC in the license is the same as the card you are actually using. If you have a laptop/notebook that may not be the case at all. I suspect this is the root of your problem. If on top of that you use a docking station, with yet another network card inside, chances are very high that something goes amiss. Basically, you must make sure of 2 things: That the network card with the license-carrying MAC address is not deactivated, and that it is on top of the list in the registry - see the document attached, made by Mark Fischer of PTC some years ago. Then it should work, though you may have to reinstall if you want to change the license to a different card. The licensing procedure is causing me lots of troubles also. And frankly it is outrageous that you have to mess with the Windows registry in order to run a licensed application. I hope they correct that for WF5.