Does anyone else have an issue with Sonar and/or plug In Manager taking forever to load? I am running Win 7 64 and this just started about 2 updates ago but when I click the Sonar icon I have to stare at the splash screen for 12 minutes (yes I timed it) before the program will actually load? Same thing with Plug In Mgr except it doesn't do anything until 12 minutes later it will pop up. Also, after I do a plug in scan it will complete the scan but then hang there and say it's not responding. Any ideas?

Have you tried opening a brand new project ?
 
Something is preventing the scan and Sonar from completing the necessary set up task (obviously).
Which in my opinion is probably a plug in. If you are trying to open an already established project and your waiting for ever,
Try opening Sonar in Safe mode.
 
To do this:
Safe mode is activated when you open a file while the SHIFT key is pressed.
 
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Dialogs2.094.html
 
I would be looking for a plug in you may have installed in the last 2 months or so.
Maybe a 32 bit plug in on a 64 bit system. Or a large sample library Synth plug in that is having issues finding the samples.

As Chuck said, it's always a bad plug in. Weird free 3rd party plug ins are often buggy, I ended up deleting all of those from my system now and only use the Sonar and Air stuff. 
I also set the plug in scan to manual as it not really needed once your all set up. Sonar loads in 5-10 sec on an ssd. 

It's the quantity of plugs you have. You get over 1000 and Sonar will behave this way.

Also make sure there's not a plug-in for a splash screen hidden behind another screen. Sometimes if there's no response it will stay up seemingly forever but then time out.

Anderton
Also make sure there's not a plug-in for a splash screen hidden behind another screen. Sometimes if there's no response it will stay up seemingly forever but then time out.

THIS 
 
ALT TAB and find it hidden ... or mimimize the open screens
 
happens to me all the time with buggy plugs

macsthesword,
 
I had the same problem, for days I could not resolve the issue. My problem was my virus software " Malwarebytes Premium". I deactivate the software and Sonar Platinum loads in 5 second and plugin manager loads and scans in less than 15 seconds. I tested this several times, when I activate Malwarebytes Sonar is almost a minute loading and plugin manager takes several minutes scanning stating " not responding". So before I run Sonar, I deactivate my virus software first and Sonar runs with no problems. Try deactivating your virus software.  

Good point above. Open your Anti virus and make an exclusion for Sonars Plug in manager and any other Exe in that folder including Sonar.Exe.
 
Johnny brought up a good point earlier though, in my travels, it has been some free VST plug in that has reeked havoc.

And as I said, why bother scanning every time? You only need to run the scan when you add a new plug or VST. 
 

I wouldn't scan every time either, I have mine set to manual.
Unfortunately though, the plug in manager activated each time Sonar opens even when its not loading plug ins. Trust me I went through extensive testing on this when it was introduced.
Add: Plug in manager.EXE to your exclusions in "C:\Program Files\Cakewalk\Shared Utilities".
Also note there is a difference between the Plug in manger and VstScan.EXE Which is in the same folder.