This is a strange one that I've never experienced before in any DAW.  Whenever I do a scan of my plug-ins, the scan takes place and at some point I get a message saying "Windows is shutting down" and Windows shuts down.  It's not a crash or anything it's as if it triggers the shutdown button.  I'm using windows 8.1.
 
Martin

I am guessing one of the plugins is having a bad hair day.
 
Is it getting to a certain plugin and then calling it quits?  What do you see in the little toast message that pops up while scanning?
 
Are all of your plugins licensed?
 
What sort of plugins do you have?  (old 32-bit ones?)  Freeware ones?
 
Have these all scanned in prior releases of Sonar?
 
Is it possible that your audio interface drivers do not like Windows 8.1?  THis seems to be reported quite a bit out on the web, like prior drivers for Windows 8 are not working in 8.1 - that sort of thing.
 
Bob Bone
 

Hi Bob,
The last time it happened (just before I made the topic here) it got to Tone2 Rayblaster and the shutdown message appeared. I have no freeware plug-ins. Probably the oldest one in NI B4 32bit. I thought at one point it was my MidiQuest plug-ins but I removed them beforehand and it still happened.The scanning happened OK when I first installed X3 although I have added plug-ins since. Maybe it's related to my Windows 8 > 8.1 upgrade I did recently? I try again and see when it happens this time. Did notice the toast message but I will look next time.
 
Thanks
Martin

OK so Tone2 Rayblaster and Saurus were the ones causing it. So I removed them and scanned again. Then I put them back in and did a "rescan failed plug-ins" and they passed. So at least i found a solution although I'm not sure why they would have that effect. Now all I need to do is somehow get Session Drummer 3 to show up.