Sonar Tempo problem - Project audio suddenly runs really slow

 
This seems weird, I'm working on a project which currently has 16 Audio tracks and 12 AD2 midi tracks with a tempo of 98 which seems to work ok, then for no apparent reason (ok I know there will b e a reason) when I play the project it has slowed down to a snails pace. on the last occasion this happened I armed a track ready to record hit Record and it went really slow.
If I close Sonar and re-open it still goes slow no matter which project I open it's the same.
 
If I re-boot my PC it will fix it for a while.
 
I should point out that this is a brand new PC that I have just installed Sonar on - but I have checked the settings with my old PC and it's all the same. (apart from a different audio interface, I'm now using a Universal Audio Apollo Twin Thunderbolt MkII)
 
I've checked the midi file to see if there are any 'Events' that might change the tempo but I can't see any.
 
Even if I load a project without midi, it still runs slow.
 
Any ideas what might be causing this would be appreciated?
 
Thanks
Al.
 
 

Thanks for the reply - I have just checked the Windows Audio Sound bit rate and sample rate 'recording and playback' and they are both  set to '32bit 44100'
 
My Sonar Audio preferences has the default setting of 44100 as a sample rate but the 'Audio Driver Bit Depth' is greyed out and says 24bit
 
Could the bit depth be problem?
 
 

Hmmm, it was ok for a while, and now the problem has resurfaced.  
I can play the imported audio file in Media player without problems
 
Struggling here :(
 
 
 

Do you have the latest drivers for it?
Do you have "Share drivers with other programs" checked in Preferences (P), Audio, Playback and Recording?
If so, perhaps uncheck. 
Edited: Saw your AI was a UA device, and removed first sentence of my post.

What driver mode are you running (asio or wasapi)? There seems to be an issue with some drivers and armed tracks that was introduced in Sonar 2016.10. that causes exactly what you describe. It took me forever to track it down as it seems almost random. I encountered it when using Wasapi mode with an x32 digital mixer. It may or may not be what you are seeing, but it is easy to test.
 
When the slow payback happens, stop playback and use the master switches in the mix module on the control bar to disable echo input and record arm on ALL channels, restart playback and see if it returns to normal.
 
If this is the issue cakewalk are aware of it and are looking into it.

Thanks for the info,
 
I'm using the ASIO driver mode (Is this preferable?)
 
My Clock source in Sonar = 'Audio'
My Clock on the Apollo = Internal

Do you have a pick in your clock source (in Sonar) to something that represents your Apollo?

I have just noticed that in Sonar Preferences_> Audio-> Sync and Caching under File system Playback and Record I/O buffer size  is set to 256 , and the Buffer size settings in my Apollo I/f was set to 512. So I have changed this to 256 to match the DAW and will see if this cures it.  

also make sure your windows power mode is set to high performance VS. Power save.
your interface could be going in to power consumption mode and thus the reason a reset is temporarily solving your issue.
(Windows Power settings = in control panel)

I have had a similar problem in the past which has not happened for a while. However, when mine did it the sound would become distorted and slow right down - you didn't mention anything about distortion so not sure if it's related. It did this with two different Focusrite sound cards - Safire and Pro 40. It would be random and occasional. What version of Sonar are you using?