Mac devices do not have a registry in which to store the identities of licensed software and accessories as Windows devices do, so software needs to be associated with a device name in order to run. If the device does not have a name, it cannot be associated with a software program, in this case Citrix/VLab [1], and so it does not run. Here's how to fix it:
Citrix Receiver for Mac should now run correctly.
More information and screen captures are available on the Citrix website [2]..
Links:
[1] http://www.humboldt.edu/its/glossary/5#term229
[2] http://support.citrix.com/article/CTX136343