My win 8.1 installation is saying that mfc110u.dll is missing when I click the sonar icon. Not sure how to fix this as I uninstalled and then installed and get the same error.
 
Its only sonar producer affected (Ableton) and other daws work fine.
 
if anyone can shed light on this it would be appreciated.

At work right now and can't look things up to easy. But there is a certain procedure for a clean uninstall. Look that up ( or someone may provide a link) and follow those procedures to uninstall Sonar. Then reinstall and see if that helps.

I believe this is a standard part of Windows and not Sonar specific.
Try the standard system file fixes at an administrative command prompt:
 
>sfc /scannow
 
and/or
 
>Dism /Online /Cleanup-Image /RestoreHealth
 
See this for details:
 
http://www.eightforums.co...ption-windows-8-a.html

It's not the problem with this program, it's problem with your Microsoft Visual Studio 2012. You should try to found this file on your PC. If it's missing - try to reinstall this windows component. You could also try to find this file in internet and download it, for example from  and add it to your windows/sysWoW64 folder. It should fix your .dll error.