I was working on a new mixing template using Aux tracks for FX and instrument busses with the default Master buss as the Master buss. I inserted VTM on the master buss and was testing the signal paths with a single audio track with a bass guitar loop when suddenly, I hear nothing but white noise. I disabled VTM and the noise when away and I could hear the loop again. Any ideas as to why this is happening? 

Tape hiss?

, it could be a setting on the Tape Machine, See if there is a wet and dry setting. it may be all the way set to wet.
 
OR; Is there a demo mode for that plugin?
 
CJ

If its tape hiss it is really loud. You cannot hear anything else but the noise. I don't think that its hiss though.

doment500
If its tape hiss it is really loud. You cannot hear anything else but the noise. I don't think that its hiss though.

A plugin of that caliber (Slate Tape Machine) , can produce the noise you are explaining. Like i said, check the setting, especially the "Hiss Auto Mute" setting and the "calibration" settings in the Virtual slate tape machine.