I posted a thread on this a few weeks ago as I had taken advantage of the copy of Sonar Home Studio that came with last month's Computer Music to update from Sonar 8LE. I also bought myself a larger SSD to replace the 40Gb one that kept running out of space and updated to Windows 10. I've had similar problems with the IK ST 2 based VSTi s which is really frustrating as they are just about the only ones I have paid for (I got a couple of group deals on the instruments and the sound collections) as most my others have been freebies with CM or downloaded from the web! The other main VSTi it doesn't recognise is Air Xpand (which I paid £1 for and like very much!) even though I've tried reinstalling and reauthorising it through ilok.
HS also doesn't recognise the free ST 3 but I am thinking of trying to reinstall it and seeing if it can read the old libraries - I am not hopeful though!
Oddly Sonar HS recognises all the derivative plugins apart from ST2 itself though they do seem to cause problems when they are loaded and rarely work for long before crashing. Apart from Miroslav 1 which I have used a lot I don't have any important projects that rely on them but it is still very frustrating after forking out a fair few quid for them. I am trying to decide whether to cut my losses or persevere!