"License of Rhinoceros is already in use" warning

Product: Zoo 4.0
Summary: Solving the “License of Rhinoceros is already in use…” warning.

When I launch Rhino 4.0, I get the following error:

This license of Rhinoceros is already in use on <COMPUTER NAME>.

You can receive this message if:

1. The same Rhino 4.0 CD-Key was used to install Rhino on more than one workstation.
2. One of Rhino 4.0 CD-Keys you added to your Zoo 4.0 server was also used during a stand-alone node installation.

If all of the workstations are supposed to be running as workgroup (or network) nodes, which obtain their licenses from a Zoo 4.0 at run time, then you can solve this problem by following these steps.

1. Launch Rhino 4.0
2. Pick Help → About Rhinoceros.
3. If the About dialog box reports that it's license is stand-alone node, then:
   1. Close Rhino and restart Rhino by running it as an administrator.
   2. Pick Tools → License Manager → Workgroup Node.
   3. Close Rhino.

When you start Rhino again, it will be running as a workgroup node.