I've been using 32 Platinum and am trying to transition to 64 bit, yet today I tried 64 bit Platinum and it doesn't work with StudioMix. Under control surfaces, StudioMix shows up and I assigned my MidiSport midi interface to it and hit apply and the midi interface disappeared in the control surfaces window. After closing preferences it's still not showing up in the Control Surface toolbar.
 
Has anyone been able to use StudioMix with 64 bit Platinum.? It works just fine with 32 bit

Yes...

I'm using it here. Running SPlat x64 on windoes7Pro x64.

I'm not having any trouble with it.

I'm trying to understand your setup... The studiomix shows as a control surface and within its setup I reference the midi port to use. I have even changed midi pirates couple of times and it continues to work the same after I edit the midi port selection...

StudioMix? Wow. That is what first drew me to Cakewalk Pro Audio. How far things have come!
 
http://www.soundonsound.c...99/articles/peavey.htm

The problem may relate more to the MIDIsport than the StudioMix.

Keni
Yes...

I'm using it here. Running SPlat x64 on windoes7Pro x64.

I'm not having any trouble with it.

I'm trying to understand your setup... The studiomix shows as a control surface and within its setup I reference the midi port to use. I have even changed midi pirates couple of times and it continues to work the same after I edit the midi port selection...

 
I'm using Win 8.1 Pro. I have 2 midi devises one that's included with the AVB Ultralite sound card and the MidiSport. I open preferences, choose control surfaces, choose studiomix, then choose the midi ports. Hit ok and the ports I chose do not show up in the preferences control surface window like they do in 32 bit Platinum. If I delete the control surface and then start all over using the other midi devise – same thing. I hope this isn’t another Win 8 bug. I wonder if anyone using Win 8 has StudioMix

Anderton
The problem may relate more to the MIDIsport than the StudioMix.

I was wondering the same thing, so then I tried it with the AVB Ultralite midi interface that's built-in and I have the same problem.

Not any of the midi interfaces listed, but I have success with win7pro x64 and either the Presonus 1818vsl's midi port or an editor um-2 which I use to have extra midi ports as my magic unitor8 interfaces (yeah, I've still got two of them) require serial ports which modern machines no longer have... I've been told the will not work with converters either... And I thought to add a serial card but I'm out of slots...

Make sure you don't have 32 bit drivers installed for it, only 64 bit drivers.
That used to be my issue with my Faderport.

Thank you, azslow3. I installed 64 bit X3 and now StudioMix works fine in Platinum 64 bit. I hope Cakewalk sees this post and fixes this oversight in Platinum. What about the poor suckers that don't have X3?