whereabouts are they installed? if under the "program files" hive, try installing them outside of there like c:\somefolder\... this will mean the security trimming on program files folders won't be a part of the issue... this is why it's good practise not to install VSTs under "program files" (even though daws tend to default to there, a hangover from the olden daze) and that's why you have to "run as admin" in the first place...
/hth good luck

UPDATE:
Eventually I decided not to run Sonar Platinum as administrator and to disable the problematic IK plugins. Instead I've set Sonar X3 to run as adinistrator with the plugins enabled there. For those occasions when I need to use Miroslav or SampleTron or whatever, I will save a copy of the project, edit it in X3 and export the rendered result to import into the main project. This is not too different from my usual workflow MO anyway, so it shouldn't be too much of a problem.

scook
Be aware, if you ever use patch points or aux tracks, the project will not open in any version of SONAR that does not support the feature.

 
Thanks. I'll watch out for that. I've been using aux tracks a lot lately.

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!

Thanks - I'll probably spend a few more hours trying to get them to work but I think after that I will have to admit defeat - the GUI is pretty clumsy and fiddly anyway so I may just have to treat myself to a new rompler and orchestral set 

I've tried loading Sampletank 2 instruments in Sample Tron / Sonik Synth but unfortunately just get the message 'This is not a Sample Tron / Sonik Synth Instrument' so cannot be loaded. Tried loading them in ST 3 Free but that didn't work either - though I may not have the latest ST3 Free - will check that now

JoeGBradford
I've tried loading Sampletank 2 instruments in Sample Tron / Sonik Synth but unfortunately just get the message 'This is not a Sample Tron / Sonik Synth Instrument' so cannot be loaded. Tried loading them in ST 3 Free but that didn't work either - though I may not have the latest ST3 Free - will check that now

Again, it's been awhile, but I'm pretty sure Sampletank has to be the "master" program (You can load the other instruments into Sampletank, but not the other way around).  I used to access Miroslav and Sonik Synth sounds from inside the Sampletank interface.
 
With ST3, I'm not if you can directly load the older libs -- you may have to import them first.

You have to import ST2 into ST3, but it's pretty painless except for disc storage.