I've got Sonar Platinum, with the latest Ipswitch update installed, and I'm having trouble using the Piano Roll View (PRV), to edit a midi file.  
 
I have the PRV open in full screen, and the midi track is solo'd.  I start playing the midi file from the beginning, stopping and starting as I detect mistakes in the midi performance.  I then correct the error and hit play again.
 
Randomly during the starting and stopping, Sonar will just freeze, and I get the spinning windows 10 mouse icon.   I also notice that the synth track and master out level are frozen at their current level.  
 
I've waited up to 15 minutes for Sonar to respond again, but it never does.  I then have to force close Sonar, reboot windows, and start the process over.  Trying to restart Sonar alone, does not work. 
 
FYI.  I've tried several different softsynths, but it does the same thing regardless of the softsynth.
 
Any suggestions?

Another quad-capture...
 
Suggest
 
Update your quad capture drivers and firmware from Rolands site.
Delete AUD.INI in Cakewalk (google for details).
Rule out a problem plugin by starting Sonar is safe mode.
 
Try a different soft synth (what exactly are you using? Is it 64 bit?).
 
Cheers...

I have the latest Quad Capture driver installed.  According to Roland's website, Windows 10 automatically downloads and installs the correct driver when the Quad Capture is connected to a Windows 10 system for the first time.  There is no new driver on the  Roland website.
 
I can try deleting the Aud.ini file tonight, and see if this helps.
 
I'm not sure if safe mode will help in this case.  Sonar loads fine.  Everything so far is working fine, with the exception of editing midi in Piano Roll View.
 
Yes.  64bit.  I've tried several different synths.  Dimension Pro, Rapture, Sampletank, EZ Keys.  The PRV freezes with any of them.  
 
FYI.  I only have the one midi track in this project.  All the other tracks are audio.  I'm at the late stages of this project, and there were some performance errors in one of the audio tracks, that I wanted to correct, so I imported the original midi track and loaded up a synth. 
 
  

Doktor Avalanche
Another quad-capture...
 
Suggest
 
Update your quad capture drivers and firmware from Rolands site.
Delete AUD.INI in Cakewalk (google for details).
Rule out a problem plugin by starting Sonar is safe mode.
 
Try a different soft synth (what exactly are you using? Is it 64 bit?).
 
Cheers...

davec69
I have the latest Quad Capture driver installed.  According to Roland's website, Windows 10 automatically downloads and installs the correct driver when the Quad Capture is connected to a Windows 10 system for the first time.  There is no new driver on the  Roland website.

 
Some issues get resolved by removing, rebooting, and reinstalling the driver. Occasionally Windows 10 needs a driver to be refreshed. I assume you installed the latest system update (1.0.4), that won't be automatic.
 

davec69
I'm not sure if safe mode will help in this case.  Sonar loads fine.  Everything so far is working fine, with the exception of editing midi in Piano Roll View.

 
Almost anything in a DAW can trigger off a problem plugin.
 
Also forgot, suggest you update your display driver to the latest as well direct from the display driver manufacturer site.

Prior to Windows 10, I was in Windows 8.1 with the 1.52 and 1.04 drivers for the Quad Capture.  
 
I'll remove and re-install the driver and see if that helps.
 
I just updated the Display driver last night.  
 
 

In case you want to do further research...
https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=%22piano+roll%22+crash+sonar+site:forum.cakewalk.com
 
Cheers...
 
 

Thanks for the link.  Looks like various PRV problems have been around for a while.  Hopefully, I can get it resolved on my system.  

Did you get you issue resolved?  I have similar problems on my system, which basically has the same specs as yours, except for audio interface (Scarlett 2i4).
Since I installed Platinum, I only had issues happening in PRV, nowhere else.  Would really like to get this resolved.

Delete... Mistake.

Still no resolution.   Not sure what's going on.  I'm hoping the next update fixes whatever is happening.   I'm also getting random freezes in the main view.  Usually after i click on something.  I get the spinning icon, which doesn't go away until a restart.