Firts of all my hardware/software :
- Intel Xeon 6 core processor
- 24 GB DDR3 RAM
- SATA 3 SSD with 550MB write/read speeds
- Windows 10 Pro x64 edition latest version and all hardware drivers are latest too.
- Tascam US-366 USB Interface with latest  driver and firmware Connected via optical spdif 
(My system is rock stable and has no issue). 
 
I am demoing Sonar Platinum 64 bit. I get random Whistle/Feedback/static  as soon as I hit the playback button from the start of any playback until I stop. The next  start playback usually is normal. These whistles get more frequent if I get to higher sampling rates. Any sound file imported without any fx is doing that. There is no such behaviour with  other DAW brands.  
 
Here is what I did and get no improvement on fixing the  problem :
- Increased ASIO buffer size
- Tried all sampling rates
- adjusted lots of  buffer sizes on preferances screen of Sonar
- loaded lots of types of 
- tried all types of dithering methods
- checked and unchecked  64 bit internall precision
- gave Sonar exe  all types of  CPU affinity options with  windows
-  gave sonar exe   admin rights
- armed and disarmed metronome with  all kinds of tones
-  inserted lots of different  effects
 
Solution:  Installing previous Tascam 1.03 driver solved all the issues.
 
 

Are you using a wireless mouse?

Yes, I am using a wireless mouse. But I don't think it is  affecting the overall sound because  these are  no background noise just plain note whistles. No sound of any track, just feedback. Also this issue is  on only Sonar not the others. 

You don't have any plugins in demo mode in the project? 

With or without any plugins inserted it is the same. 

I assume you're using the TASCAM drivers and not ASIO4ALL?

I'll try asio4all and reply back. But still the only daw is sonar for the issue. The GUI of sonar is great and seems pretty straightforward for projects.  I hope rectifying the problem soon. 

Asio4all has no such issue . But it is not as stable as Tascam's driver. The reported  roundtrip latency of asio4all is lower but I can hear a subtle latency when playing my guitar realtime using any guitar amp sim. Also CPU usage is a bit higher than normal.  
 
 

Try turning off the "64-bit Double Precision Engine" in Preferences > Audio > Driver Settings.

Solved by installing old official driver of Tascam from 1.04 to 1.03.  Thanks people for pointing out the sound drivers.