dke
As far as CPU meters they rarely show any activity at all on this particular project and when they do it's only a sliver of green shows.  The disk activity meter on the other hand is running in the red very high up to 99%.  Windows Update is not running/checking nor is anything else, Sonar is the only thing running and using the disk of any consequence.
 
I think this started with the Aug update 1, not the original Aug update or possibly the 2016.09 pre release. But as I said before rolling back does no good which is why I'm thinking it might be the C++ runtime update that seems to have been installed wiith the Sonar update. Nothing else has changed.  Even if Windows Update also did some updates that's not likely the problem or more people would be having problems, not too mention it's not like we have a choice any more.  I'm not going to stop updating Windows just so Sonar will behave...
 
I really hate to uninstall/reinstall everything but that's about all that's left to try.
 
Dan

Hi Dan,
>>the disk activity meter on the other hand is running in the red very high up to 99%. 
 
You are sure you are looking at the disk activity and not the Disk space meter right? If so this will require some investigation because this surely the reason for your drop outs. Its not enough to compare with another application since you are not referencing the same files.
 
Here are some suggestions for troubleshooting it:
 
1. Click Ctrl-A to select all clips and then click shift-K to open the associated audio files dialog. In there look at all the file paths and the bit depths and see if they are expected. Are you referencing files on other drives, are the bit depths 24/32/64 etc? Too much 64 bit audio can put a strain on the system if your disk can't keep up.
 
2. Clear your picture cache folder open the project and let it finish rebuild. Now start playback and check if it changes the disk activity percentage?
 
3. Double check if the project was accidentally audio snapped or has a lot of region effects (melodyne).
 
4. As an experiment select all ctrl-a and copy and paste the audio tracks into a new blank project. Now start playback from there. Do you see the same activity?
 
5. Do some disk analysis on the drive where all the audio resides.
 
6. If you have a prior version of SONAR load the project there and compare performance.
 

Unfortunately I've done all but #1 multiple times, which I'll try.  As far as trying in another app, the files were identical loaded from the same Sonar project directory.  Since I'm using no effects it was a quick and easy test to do. I don't expect them to be identical, but it eliminates the drive and files as the problem pretty much. It is just 62 stereo audio tracks, 16k/44.1, no mixing, no effects, nothing, playing 1 solo'd track at a time.
 
I have installed the Windows Anniversary Update but this started before that.  I was hoping that might fix the problem but no luck.  I've reinstalled video and audio drivers
 
My other projects that I've tried so far are working fine, even though they have effects, instruments, melodyne etc., but they are typically 25 tracks or less.
 
 
I'll keep searching...
 
Dan  

Are you reading the wave files from a HDD or SSD? If a HDD even though you defragged, they may not be close to each other on the media so two things to try.

Save the project as a bundle file and launch it, this will often unpack the wavs close together.

Under Sync and Caching (advanced mode in preferences), bump up the disk I/O buffers to 512 at the bottom of that page. Do not confuse those with audio buffers, that is buffers on the disk itself.

Also check out your system event log(s).  You might have a marginal drive.

mettelus
Are you reading the wave files from a HDD or SSD? If a HDD even though you defragged, they may not be close to each other on the media so two things to try.

Save the project as a bundle file and launch it, this will often unpack the wavs close together.

Under Sync and Caching (advanced mode in preferences), bump up the disk I/O buffers to 512 at the bottom of that page. Do not confuse those with audio buffers, that is buffers on the disk itself.

It's a Hybrid HDD, I've already tried the disk I/O buffers settings.  I've tried the bundle idea, as well as copying the project to another drive and trying it from there. Thanks for the suggestions though.
 
Dan

Any chance you can share the bundle file with us so we can look at it?

BobF
Also check out your system event log(s).  You might have a marginal drive.

I've checked them, nothing out of the ordinary.  As I've said I've tried different drives, the computer itself is only 6mos old.
 
Dan

dke
Unfortunately I've done all but #1 multiple times, which I'll try.  

 
Did you try this?
6. If you have a prior version of SONAR load the project there and compare performance.
 
Try this on SONAR X3 or earlier for example assuming you have it installed. If the same happens there then its definitely system dependent somehow.

Hybrid drives seem to be trouble.

Noel Borthwick [Cakewalk]
Any chance you can share the bundle file with us so we can look at it?

With 62 audio tracks that bundle is likely large (3GB-ish), but definitely consider sharing that with Noel. I am not sure of limitations for Google drive and the like though, or your upload speeds.

Just for clarification, are these tracks single files or contain multiple clips? Do they contain any AudioSnap data? Saving/reopening a bundle should strip out AS data, so is indicating more that preferences may be influencing things. Have you tried bumping up the audio buffer as well?

An easier route would be to let Noel look at that bundle file since troubleshooting via text is a royal PITA sometimes.