I have been recording acoustic guitar on a sonar 8.5 audio clip, and every time about 4 minutes into the4 clip there is this tempo/key change.  I have even opened a brand new project, saved under a differnt name, rerecorded the piece, and the same thing happens.  How can I find where this key change is occurring?
 
Thanks,
Dave

Key & Tempo changes only affect Midi. From the sound of it you're recording audio yes?
 
Which version of SONAR are you running? what are you using for an interface?
Please list everything about your system
 
 

Under the views menu, is there a "tempo" and "Meter/Key" item?  I Can't check myself as it's been ages since I have used Sonar 8.5

Sound card is echo Gina3g.  Plugging guitar direct into universal input interface.  Yes -- audio track.
Sonar 8.5
Windows 10
 
 
 

Did you open the tempo map? 
Does the tempo display change at this point? 
Are you playing along with a midi drum track? 

I did open up the tempo view -- nothing there.  No drum track either -- just acoustic guitar into an audio track.  
 
Update.  I recorded two more tracks without it occurring, then did another take, on another track, and it happened again.  Confounding.

Does the tempo display change at this point? 
 
You didn't reply to this.. Its important. 
If the answer is yes, then there is something somewhere changing tempo. 
Just start a new project and use a clean template. 
If No then this might be audio drivers or a ?  That's a very old card is it not? 

The tempo display does not change.  I did another take and the problem did not reoccur.  Also -- it happens at different times into the recording too.  Once at 4 minutes, another time at 4:15.  This is also the 3rd differnt fresh template I have started with.  and yes -- old card.

Another update.  One of the recordings that did not have a tempo change, all of a sudden...did.  In fact, it changed the whole speed of the vocal too making me sound like a munchkin.  I restarted sonar, and the problem went away.  Obviously, I have some issues either with the old card, or the older version of sonar, or windows 10.  Am installing the latest 8.5 [patch now.  

OK that is a huge clue. If the pre recorded audio speeds up and plays at a higher pitch then we've nailed the problem to your audio drivers are somehow changing sample rate. 
This should never happen, but can happen if you have Sonar open and then open another App that plays music and changes your playback sample rate. 
I have not had this happen for a long time with my currant 2 audio interfaces but this used to happen back when I used a M Audio card. 
 
I you are not leaving Sonar then this is defiantly a issue with your old cards driver instability. 
 
That's seems odd that your "just" installing the 8.5 patch. I sure hope this is not a pirated version. 
With Sonar Home Studio @ only $50 there's no reason not to update.