This is exactly the problem I am posting about. The same error msg verbatim, except that mine references RegSvr32, and even occurs on the same Stretch.ax file.

Make SURE Windows maintenance is completely up to date, as there are now Sonar dependencies on Windows pieces that only exist through the installation of Windows maintenance.
 
When applying Windows maintenance, you will need to run Windows Update multiple times, because there are frequently updates to the updates, so you get a 'layer' of maintenance, then you have to check to see if there are updates to that layer - and that will apply another layer, and so on - until it finally checks for updates and comes up with no more to apply.
 
This may well take several passes through running Windows Update.
 
Also, after it applies maintenance, and you restart Windows, it may tell you there aren't any more updates, but it may not have checked after the restart, so run it one more time and see if it really is the end of needing to apply updates.
 
Bob Bone
 

I had the same issue with a completely updated system. The OS install is pretty new and the system had never had any version of Sonar installed on it.
 
I tried rebooting and re-running Windows Update, but still no luck.
 
I then tried manually installing the redistributable packages (both x86 and x64) and still no dice. 
 
Just before giving up I tried one more reboot and now things are working. it looks like the system needs to be rebooted after installation of the redistributable packages in some cases.
 
I hope that helps someone.

In case it's of use to anyone else, I gave in and did a complete reinstall (initiated thru HP's Recovery utility, but basically a complete Windows reinstall) and all is well now. Clearly corrupted files that Refresh didn't help. Nothing else did either.

Lots o' time lost on that one.

Oh well.

Cheers.

Ah sorry I missed this..
 
Installing Windows media player and/or the media feature pack could have helped... Maybe useful for the next person....
https://www.cakewalk.com/...ror-for-Missing-MF-dll

 
This thread helped me complete first time installation of SONAR Platinum Jamaica Plain Version under Windows 10 on Surface Pro 3. I am new to Windows 10 and had just upgraded the Surface from Windows 7 to Windows 10. I received the "Unable to register the DLL/OCK: RegSvr failed with exit code 0X3" dialog for Classic FX, Artist Instruments, and Platinum Instruments SONAR modules.
 
After reading this thread I checked for and installed Windows 10 updates. Then tried again to install the three SONAR modules that had failed to install running Command Center as Administrator and with the Windows Firewall and AVAST Free AV active. It worked! My SONAR installation is complete.
 
I'm not sure that running Command Center as Administrator was necessary as I didn't try to install the three failed modules as non-Administrator after completing the Windows 10 updates.
 
Though the three failed modules installed fine with Windows Firewall and AV active, I'm not sure the rest of the install would have completed with them active. I had turned the Windows Firewall off for most of the installation and had turned the AV off when I started dealing with the three failed modules.
 
This old thread continues to be helpful!!
 
Bill

I Have Windows 7 Home Premium / Sonar Platinum and I have followed thread with all suggestions and I still see: 
Install error - Unable to register the DLL /OCX:RegSvr failed with exit code 0x3
 
Is there a Link to a Step by Step Process"
 
I watched a video fpr Nero with the same problem but user was using a different platform.
 
Any Assistance would be incredibly appreciated. 

Jereb, I'm not aware of a step-by-step process link. This thread is the only thing I'd found. As for me, I used my normal Command Center install process of individually installing each module in the command center expanded list. It's more tedious, but it allows me to better track progress and deal with issues when there are any. To my knowledge, all I did to install failed modules was turn off antivirus and firewalls and then run Command Center as administrator to install failed modules.
 
Bill

jereb
I Have Windows 7 Home Premium / Sonar Platinum and I have followed thread with all suggestions and I still see: 
Install error - Unable to register the DLL /OCX:RegSvr failed with exit code 0x3
 
Is there a Link to a Step by Step Process"
 
I watched a video fpr Nero with the same problem but user was using a different platform.
 
Any Assistance would be incredibly appreciated. 

You will receive this message if the RegSvr32 service is being blocked. This is a Windows process we call to register components. 
 
You will need to complete any pending Windows Updates and restart the computer before attempting to install SONAR again.

That message means that regsvr32 couldn't find the file or a dependency of it, and it's a shame that it doesn't tell anyone which file.  The reason this thread mentions the Visual C++ Runtime is that it is a typical dependency, and C++ Universal Runtime can be an issue:
 
https://support.microsoft.com/en-us/kb/2999226