Sometimes you find yourself in one of those situations when nobody seems to have an easy solution, so you have to find one for yourself. For instance, you may need to connect to your VDI, and start your Skype meeting only to find that your microphone is disabled (in Skype, in Control Panel > Device manager).
And the answer is
to add AllowAudioInput=True
to the section [WFClient]
of wfclient.ini file
of your Citrix client configuration
So, here is how to fix it in slightly more detail: