I had an issue after upgrading SD2 that samples would load up to about 90% of the expected RAM usage, and then just stop.
I eventually figured that the installer had put the new DLL in
C:\Program Files\VstPlugins\Toontrack\64bit
I had to copy it over the old DLL that SONAR was loading from
\Program Files\Cakewalk\Vstplugins\Toontrack\64bit