It works fine with my Vista 64. I have found that most products that work with Windows 7 are still working fine with Vista 64. The X2 fix to LP64 was a great addition when it came out, a fix I had been waiting on for a long time. LP64 always sounded great but was almost impossible to work with in its old glitchy state.

I was speaking of the X2A update, which requires a collection of C++ routines that only came into existence on Windows 7 SP1, from my understanding of it.
 
If you were referring to X2, it may well run on Vista, and on XP as well, but then that would be the end of the road.
 
If I understand it correctly, the installer itself fails upon detecting those C++ routines not being present.
 
Bob Bone
 

Please note: SONAR X2a is only officially supported on Windows 7 and Windows 8. Installation is not possible on unsupported operating systems, such as Windows 98 & XP. It remains possible to install and use SONAR X2a on Windows Vista though it is not recommended.  
 
Bob,
 
It's been a really long time since I did any upgrades to X2, but I believe that I have X2a installed on my DAW.  It's definately in my downloads folder and I see files that were updated on 12/18/2012, which is when the patch would have come out.  I found the above on Cakewalks X2a patch link.

Wow - good thing I tried to communicate that my info was only as good as my brain remembered, and not absolute fact.
 
Apologies anyways, as I could have double-checked it and didn't, so I was still lazy.  :)
 
(I was tearing what's left of my hair out trying to figure out keyboard solo notes in a muddy mix)
 
Bob Bone
 
 
 

Bob,
There seem to be a to of products out there that say they don't support Vista, but if I try them, they actually work fine. Like my Focusrite 8i6 says that Vista 64 is not supported and it seems to run fine. I know that my computer is constantly going through Vista upgrades automatically, I will find the message on my screen in the morning about every 2 weeks. I am assuming that it is really close to W7 at this point. MS had to change the name with all of the bad publicity that Vista had back then. I honestly have never had any issues with Vista.

I have a copy of W8 sitting on a shelf for this computer, but I am not going to install it until I have to. I am relly hoping that X3 doesn't force that to happen.

yep, that fixed it.  Thanks for all of your help, e.g., ensuring SP1 installed.  Not sure why support did not recommend the fix.
 
Thanks again,
Bob (A.)

@neverwasbeen
 
What fixed it?  Getting maintenance applied to Windows?  I wasn't sure what you meant.
 
Glad you are working, in any case.
 
Bob Bone
 

No, what fixed it was installing X2 and X2A update.  I was already running Win7/SP1, so simply did the installs.  I had been running X1, and had not yet installed X2.

OK - thanks for clarifying.  I have been running X2a for quite a while now, and find it quite stable on my system.  Others have differing levels of stability, depending on several factors, such as the mix of 32/64-bit plugins, interface drivers, and system hardware.
 
There is another current thread where someone is looking for folks running X2 successfully.
 
Glad you have things working better.
 
Bob Bone