Have you gone into the IN/OUT settings of the stand alone and checked the right boxes there indicating the midi source and also the audio output and to your sound card etc..
 
My stand alone crashes the moment I attempt to get into the IN/OUT settings which is a bit weird.  The one time it did behave in stand alone mode I was able to get to that page and the settings were correct in my case.  It only plays the odd midi note too and the notes get stuck followed by a crash.  It feels like some sort of midi issue to me. eg midi signal flow.  I hope Synthmaster does not output midi data.  That might screw up my system.
 
I have got a few Arturia stand alones as well and they all work perfectly too.
 
Inside my DAW Synthmaster is totally perfect.

Jeff Evans
Have you gone into the IN/OUT settings of the stand alone and checked the right boxes there indicating the midi source and also the audio output and to your sound card etc..
 

Yes. SMaster sees my 2i4 (which was automatically selected by SM) as the midi source for IN/Output as well as audio output.......something in SM isn't doing what it shows....IDK.
 
It's not a big deal or deal breaker as I can use it in Sonar, but I like to know it actually works in standalone and test things out here.
 
On a different note, I'm also not able to use SM when using Midi Guitar.....nothing happens when I select SM as my VST instrument. All the others work fine. (just thought of this now) I wonder if I need to re-scan the VST's within Midi Guitar (just to refresh)?     

fwiw, no issues using midi controller in standalone here
 
regarding the i/o setup, if it crashes when accessing that, it seems to imply a driver issue