Then there's obviously a problem.

Will have to think on it some more then

Thanks, also to note, any Kontakt.DLL file that is in VST folder it seems to hangg on, even if it's my old version which used to work fine, have tried isolatingeach one in the folder on it's own and it hangs on anything to do with Kontakt,
 
Thanks for your help.
 
 

Perhaps you could reinstall Sonar

I have seperate installations of sonar on the System so I know it isn't that, Have tried it in X2 and X3.
 
It will run fine as long as I switch off VST Scan, but it just means next time I add plug ins and it goes to scan them it will hang and then remove them

Plenty of people here use Kontakt, myself included, and have not encountered this problem. So that makes it more difficult to find a solution.
 
I don't think it's normal for Kontakt to generate .bak files. I would try moving those out as well. 
 
There have been reports of Kontakt hanging if there is a disc in the optical drive. While I think that shouldh't matter, it might be worth checking. 
 
My guess is there is something abnormal about the Kontakt installation or update. Forumite scook is very knowledgeable about the registry, plug-in inventories, and those sorts of details. He may see this thread and have an idea of what the problem might be.
 
I don't think a re-install of SONAR would help. It already sees other VSTs, so its scan seems to be working. But apparently, there's something about Kontakt it's not seeing. 
 
I did have a Kontakt problem once where an older version did not uninstall completely while updating, and I had to contact NI tech support. They were able to fix the problem with a link to a tool that could completely remove the old version.

To the best of my recollection, The X3 Cakewalk Plug-In Manager version replaced the X2 version, so once you installed X3, both X2 and X3 began using the same version of the Plug-In Manager.  
 
I am mentioning this because of your comment about having separate installations of Sonar (X2 and X3).  BOTH of those versions now reference the same Plug-In Manager version.
 
Many times, when a plug-in hangs in a VST scan, it is due to that plugin having some kind of error condition - such as not being fully licensed or something like that.  The scanning process queries each plugin, to get back information reported by each plugin, and if a particular plugin issues some kind of unexpected response to the plugin manager, then the plugin manager may well not have a clue as to how to proceed, and it hangs.
 
I cannot tell you that the above is definitive, it is just one possibility.
 
1.  After you got rid of the duplicate dll versions of Kontakt 5, did you do a full RESET and RESCAN?  I was not sure of when you had done this, (was the reset done prior to getting rid of duplicates or after).
 
2.  The condition you are experiencing is certainly something unique to your computer, because there are large numbers of folks, myself included, that use Kontakt 5 within Sonar, and if there was any kind of wide-spread problems like what you are experiencing, many more folks would have posted as such to this forum.  This is actually good news, as it is then something that should be able to be ferreted out and resolved.
 
3.  I am a little confused as to how you came to have the duplicate dll's for Kontakt.  It almost seems like you manually moved things around in your computer.  Please explain, so I better understand how that condition came to be.
 
4.  Is it possible that Kontakt was excluded in the scan?  There is a button to click to show excluded plugins, and I believe if a plugin has been excluded there is some sort of indication there as to why it was excluded.
 
Bob Bone
 
 
 

It is an unusual problem. I don't understand how the BAK and (2) versions of the dlls got in the directory. It makes me wonder how Kontakt was installed. I did see other NI product with a (2). I don't have Komplete (guessing this PC does). I am not sure how it installs.
 
What I would do to get past this issue for now is move all the Kontakt dlls out of the VST scan path and re-run the scan. There may be more issues, so I would initially concentrate on clearing out all problem dlls until the scanner could complete. This will help access the extent problem. At least, this is what I would try first. The scanner completes (if it ever does), post back. There may be more issues yet to be discovered.
 
Edit: I see Bob has jump in. Good thing, he has experience with Komplete installs. Take Bob's advice before mine.

robert_e_bone
To the best of my recollection, The X3 Cakewalk Plug-In Manager version replaced the X2 version, so once you installed X3, both X2 and X3 began using the same version of the Plug-In Manager.  
 

This is correct. All 32bit installs share a 32bit version of vstscan.exe and all 64bit share a 64bit version of vstscan.exe The same is true about the VST inventory in the registry. The same is true with the Plug-in Manager but this is really an issue about the VST scanner. The Plug-in Manager is a separate tool.

When I first installed X3, not very long ago, the startup and VST scan took forever.  Then even longer when I did the e update.
 
Changing USB interfaces "solved" the problem.
 
I remember the old days when doing anything with a MIDI device caused Sonar/PA to hang.  It seems every audio-related USB device these days has MIDI of some form as well.
 
I would try a total power off restart on the DAW and external gear.