Freezing instruments in Play not working

It was a problem for me until I set Play to stream from memory/ram and not disk.

I am having the same problem with Play when I try to bounce tracks, too. I had this problem before, it seemed fixed for a time, and now its back. I turned off Stream From Disk, and it solved the bounce and freeze problem, but now I find Play actually clicks and glitches out -- even when I set the buffer to ridiculously high levels. This is a major issue for me, as I do orchestral stuff, and the Hollywood libraries are a big part of my repertoire. It is kind odd that this just seems to have cropped up from nowhere. I am currently working on a bigger project than usual -- with multiple instances of Kontakt and Play, and I wonder if that is part of it...

Well, all my specs are in my signature, except hard drives -- I have 5 drives, three SSDs and two WD Blacks, and most of my samples are on the SSDs, including all the Play stuff. I don't use Wifi, as I much prefer wired LAN connections for speed and stability, and ran network cable throughout my house for that reason. I closed what I was working on, and pulled up a much smaller project with only two instances of Play, 6 tracks and no other synths -- hardly a beast from a resource perspective -- and Play would not bounce nicely there, either. I suspect that this is a problem with Play and Sonar, rather than just a matter of resource management.
 
I should probably clarify that my current project is bigger than other things I have been working on lately. I have had projects this big in the past, but I don't recall any issues with Play (aside from a brief period last year, I think, where Play wasn't bouncing properly, and which was addressed in a patch - at least, I seem to recall?). Now all of a sudden I can't get Play to behave nicely, and while there are work arounds, they are kind of a pain to use.

I would think that if it plays back OK it should render in real time, too. Have you tried setting the slow bounce option? That inserts the usual wait times during the bounce that don't happen during a normal fast bounce, allowing the disk to keep up. Just un-check the "Fast bounce" box at the top of the freeze options.

I tried slow bounce, and it was better but not perfect. And while it will render in full when I disable stream from disk, the resulting audio is has artifacts in it. Using patch-points to record the solo'd track to an audio track works, and that's what I have been doing, but its a hassle. 
 
Oddly, rendering Play does work for me in Reaper. I tried that last night, and I had no problem with it. Mind you, it was only a test with 4 tracks and a couple of Play instances, so that may not be reflective of how a full project would behave. 

I've never tried to bounce or freeze Play inside SONAR, but it does Export properly without a single hiccup
 
This is from a 135 track template with drum-mapped keyswitched articulations.

msorrels
 So I've just gone back to 4.3.5.  It works, it bounces/freezes even with libraries on slow network drives and realtime playback works too.

Yeah, I may do the same. 

Real time recording of synths, the same way you would record a guitar track or vocal track, has been available for a long time.
Just arm the audio tracks for the synth and then hit R.
It's also musch faster than freezing since it records all 8 or 16 tracks at the same time.

I've found this method (for me) to be better than freezing 100% of the time.