I've read through a few similar threads but I believe my issue is different as the provided solutions haven't worked.
Using Win7 64bit Pro, when loading Sonar X3e, it hangs at the splash screen and never loads. (I have allowed it to sit and 'spin' for a few hours to no avail)
I have uninstalled and reinstalled Sonar.
I have restored my machine to a prior point a few days ago when Sonar loaded and worked fine with no resolve.
I have tried with the interface (octa-capture) on and off. ( a solution from a prior thread)
I read a thread about deleting some registry keys during the uninstall but I'm really desiring not to delve into my registry.
Does anybody know of a simple fix to this?
Or perhaps a difficult fix that maybe an old has been piano player can follow?
Thanks in advance to any help or guidance.

Try holding down the shift key while opening a project, this will open Sonar in Safe Mode, bypassing some of the issues that may occur.

Thanks for the reply!
I can't get past the splash screen to open anything. It just hangs at the 'Sonar' splash screen and never loads.

Could there be an error dialog open behind the splash screen? If you haven't checked use the Alt+Tab or Windows Key +Tab to cycle through the windows to check.

Open Task manager and see if there is a process like PluginManager or Vstscan running. If there is cancel it. Then try again holding the shift key while you double clicking the Sonar icon or double clicking a project file. That is

Shft+Sonar icon
Shft+Filename.cwp

Another thing to try is renaming the aud.INI file to aud.bak. This forces SONAR to recreate that file from scratch rather than try to map/load what is in the existing one.

I'll give both a try and see. Thanks so much guys! I'll let ya know. Thanks again.

Thanks again Guys, I got it to open, I tried the Alt+tab and Windows+tab keys with no change noted to the splash screen, and I'm not sure where the aud.ini file is, and I called myself looking hard. What I did is start some services that I noticed may be needed, it seems that a lot of services are set to manual and stopped for some reason. Now that it is open, Sonar no longer recognizes my Octa-Capture as a device. I see it available for midi in and outs but not for 'devices'. If I rescan using MME or the other drivers it shows up fine but when reverted back to ASIO the list is blank. Is there also a service that may be needed here as well, and does anybody have an idea as to what it may be? Thanks again so much for all your help!

And I am using the most recent drivers from Roland for the Octa-capture. Thanks again!

DOH! I replied from my cell and figured this would happen, sorry about that! The Aud.ini file resides in:
 
C:\Users\[username]\AppData\Roaming\Cakewalk\[SONAR Version]
 
There is one for each version. Renaming this file (to say aud.bak) forces SONAR to recreate it from scratch (but also allows you to rename it back just in case things go awry (rare)).
 
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=INI_Files.6.html
 
... shows what is contained in this file (includes your Audio Interface Settings). You can actually right click on that file and select "edit" to read it if you are curious (but I do not recommend manually editing it this way). Also bear in mind that recreating it may cause preference changes, so you will have to run through the preferences in SONAR to change some things to "how they were."
 
If things do run amok, close SONAR, delete the newly created aud.ini, and rename the aud.bak back to aud.ini (restores the original).

Thanks mettelus! I'll try it now that I can find it LOL! I playing hell trying to reinstall my octa-capture drivers now, but I'll let ya know how it goes in just a min!