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 June 29 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. 
 

 

[Rob Brown]

Yeah, no. My Windows is not compromised (in the literal sense). I have 30 years of IT experience and know what I'm doing.
I have several other DAWs installed and all of them work fine.

> What driver mode are you using in Sonar?
How could I know that when Sonar wouldn't even load? -It never gave me any opportunity to choose.
Kinda pointless after the fact. It loads fine now, and is working fine with my ASIO device (UMC).

I've used this system for years and installed all kinds of music/audio related software, so likely there is something unique to my system causing the hang. If I wanted to spend another 10 hours on it, I'd do a clean install and it would probably work, but I didn't want to go down that road.
Just one of those weird Windows things I have to shrug off, I guess.

I just put this here in case it helps anyone else who encounters it.

Thanks for the input!

 

Edited July 3 by Rob Brown

[Rob Brown]

STACK_COMMAND:  ~0s; .ecxr ; kb

SYMBOL_NAME:  ksproxy!KsSynchronousDeviceControl+ab

MODULE_NAME: ksproxy

IMAGE_NAME:  ksproxy.ax

FAILURE_BUCKET_ID:  APPLICATION_HANG_BlockedOn_DeviceIO_80000007_ksproxy.ax!KsSynchronousDeviceControl

OS_VERSION:  10.0.26100.1

BUILDLAB_STR:  ge_release

OSPLATFORM_TYPE:  x64

OSNAME:  Windows 10

IMAGE_VERSION:  10.0.26100.3037

FAILURE_ID_HASH:  {8c16a1ce-0b46-c89d-0d12-14fc7655b508}

Followup:     MachineOwner
---------

0:000> lmvm ksproxy
Browse full module list
start             end                 module name
00007ffa`9b4d0000 00007ffa`9b52a000   ksproxy    (pdb symbols)          C:\ProgramData\Dbg\sym\ksproxy.pdb\79AE11C2207ED815B76F28D1B273DBCA1\ksproxy.pdb
    Loaded symbol image file: ksproxy.ax
    Image path: C:\Windows\System32\ksproxy.ax
    Image name: ksproxy.ax
    Browse all global symbols  functions  data  Symbol Reload
    Image was built with /Brepro flag.
    Timestamp:        23D0F084 (This is a reproducible build file hash, not a timestamp)
    CheckSum:         00064B9F
    ImageSize:        0005A000
    File version:     10.0.26100.3037
    Product version:  10.0.26100.3037
    File flags:       0 (Mask 3F)
    File OS:          40004 NT Win32
    File type:        2.0 Dll
    File date:        00000000.00000000
    Translations:     0000.04b0
    Information from resource tables:
        CompanyName:      Microsoft Corporation
        ProductName:      Microsoft® Windows® Operating System
        InternalName:     ksproxy.ax
        OriginalFilename: ksproxy.ax
        ProductVersion:   10.0.26100.3037
        FileVersion:      10.0.26100.3037 (WinBuild.160101.0800)
        FileDescription:  WDM Streaming ActiveMovie Proxy
        LegalCopyright:   © Microsoft Corporation. All rights reserved.

 

[Rob Brown]

Copilot response:
 

Quote

The latest known version of ksproxy.ax—the Kernel Streaming Proxy module used by DirectShow—is 10.0.16299.334 (WinBuild.160101.0800). This version has been associated with Windows 10 and is still present in Windows 11 systems, particularly for legacy media device support.

📍 File Details

Location: C:\Windows\System32\ksproxy.ax

Type: Win32 DLL (AX file extension)

Size: ~228 KB

Function: Acts as a bridge between kernel-mode streaming drivers and user-mode applications

🛠️ Why It Matters This file is crucial for older webcams, audio interfaces, and other multimedia devices that rely on DirectShow filters. If you're experiencing issues with software like Sonar or older DAWs, ksproxy.ax might be involved in the hang or crash behavior.

 

 

[Noel Borthwick]

Sonar initializes and still uses DirectShow for the purpose of dx plugins. If something got messed up with dhow this would explain why the problem only manifested in sonar and not your other DAW's. It doesn't necessarily mean it's a bug in Sonar itself.

[Rob Brown]

But yet Sonar is the only DAW that had a problem with it and wouldn't load...
just sayin'

My point is:

Better error handling.
Sonar just freezes.
Instead of offering you a dialogue to bypass the problematic plugin.
That in and of itself is a bug.
E.O.S.
 

[John Vere]

Interesting! The only software that I use that crashes is Sonar and Vegas. They are also the only software I use that use DX plugins! Interesting for sure.