Sonar won't launch on Windows 11

[Rob Brown]

I was a dedicated CakeWalk user back in the early 90's, but drifted away from music making until recently getting back into it. When I was researching what DAW I wanted to use, I saw that BandLab was sponsoring the relaunch of Sonar and I was excited to try it out, so I signed up for a membership and downloaded Version 2025.06 (Build 034, X64), and was immediately met with disappointment when it would not launch. 

The symptom(s) were: The logo splash screen would appear and just sit there forever.
I could not even kill the sonar.exe process with task manager (admin elevated).
The only way out was a reboot.

(On a side-note: I also installed CakeWalk Next, and it worked just fine). I was bound and determined to get Sonar to work so started down an arduous road of diagnostics, uninstalling, reinstalling, updating drivers, disabling audio devices, etc., etc. Many hours were spent in vain. I eventually got hardcore and ran sonar.exe through  a windows debugger and isolated the hang/crash down the the loading of this file:

C:\Windows\System32\ksproxy.ax

Quote

ksproxy.ax is a DirectShow filter in Windows that acts as a kernel-streaming (KS) proxy module. It facilitates communication between user-mode applications and KS objects (like filters, pins, and clocks) within the kernel, particularly those managed by KS.sys (Kernel Streaming system driver). Essentially, it provides a bridge for applications to interact with hardware devices and their associated drivers that use the kernel streaming model. 

So I decided to take a chance and rename that file and reboot Windows to effectively disable it.
Disclaimer: I have no idea what the side effects of doing this are, so follow this advice at your own risk.

In order to do so, you have to "take ownership" of the file before you can rename it because it's a Windows system file and it won't let you, even in an admin elevated shell.
Right-click on the ksproxy.ax file and go to Properties/Security, then click the Users group and grant Allow to all permissions.
After that, you should be able to right click and Rename the file to: ksproxy.ax.BAK then reboot.

Once this was done, I was able to launch Sonar successfully. 
Hope this helps prevent someone else from wasting many hours of troubleshooting.

Edited Sunday at 12:48 AM by Rob Brown
spelling

[Noel Borthwick]

Hi Rob, this implies to me that your windows install is somehow compromised. What driver mode are you using in Sonar?
The kernel streaming components are typically loaded when the audio device is loaded in WDM mode (and perhaps WASAPI) but I dont believe its used in ASIO mode. I’ve not seen this component crash ever.
 

[John Vere]

The key to the mystery is that Cakewalk Next had no issues. I would have been interested to see what would happen if you installed another Daw like Waveform ( free) which is also cross platform. 
 

And make sure you download and use the ASIO driver directly from the manufacturer web site.