just recently solved the issue.
If you are using the standalone version, seeing the meters moving, but getting no sound, it is a simple fix.
although the forum and mods on here will not allow me to post up solutions revealing the adjustments to the settings.properties file.
I'll try to post it up here, but if not, find me on social media and i'll help you out.
Amplitube 5 must have left the shop working fine, but for some machines, the blank soundcard output name must have thrown it off course.
just take your AT4 settings file and make a note of your sound cards name. They have left the output blank, so no output occurs. simply put in the same name as the input, and all will be fixed.
Hope that sorts a lot of you out, I've been an Ampitube user for many years, have a Pink Floyd remake on YouTube showing Amplitube 3 (still my favourite to this very day!) but Amplitube 5 with it's ability to load custom IR's is a welcome addition.
I will say, in a mix, you'd be very very hard pressed to tell the difference, and being a kemper owner and axefx user in the past, Amplitube still cuts the mustard.
Praise indeed!