Problem turned out to be a 64 bit wav though I still don't know why the project played until recently even though it contained the 64bit wav.  The file  accounted for about 25% of disk activity by itself, added to the 40%-50% the projects other tracks were using caused the dropouts. 
 
Dan

Virus scanning?
 
I had an issue like this a while ago when Microsoft's Security Essentials 'Realtime Protection' (i.e. background scanning) had spontaneously been enabled which led to high disk usage during project loading and initial playback. The symptom that clued me in was MSSECES.EXE process shown reading audio files all over the place when a project was loaded - including files not related to the project. I added SONARPLT.EXE to the Excluded Processes list, and the problem went away.

brundlefly... Thank You so much for your input! Sonar Plat has been loading
slowly for some time for me. I tried different things but no success.
I followed your suggestion and Sonar is much snappier now. I also excluded
.WAV files so that some of my other apps would work faster too.
 
I don't post often, (don't consider myself that much of an expert) but keep
reading and learning from this community. Your tip was immediately useful to me.
Thanks again!
 
Klos Studios

brundlefly
Virus scanning?
 
I had an issue like this a while ago when Microsoft's Security Essentials 'Realtime Protection' (i.e. background scanning) had spontaneously been enabled which led to high disk usage during project loading and initial playback. The symptom that clued me in was MSSECES.EXE process shown reading audio files all over the place when a project was loaded - including files not related to the project. I added SONARPLT.EXE to the Excluded Processes list, and the problem went away.

No, I always wait till my system settles down after a restart and I've excluded my project directory from scans.  It's working great again since I converted the file to a 16/44 wav.
 
Dan.