VSTi doesn't load

Another problem I experience quite often.

  1. Create a project or open an existing one.
  2. Select any VSTi to load in the Rack (Padshop, Groove Agent, Kontakt Player etc.)
  3. The VSTi appers but it’s unusable (edit window doesn’t open although you can load presets through ‘presets cube’ but no sound from it) and cannot be removed from the Rack either.
  4. Consecutive VSTi’s seem to load fine but sometimes they (1 or 2 of them) still don’t.

Windows 7 Professional x64 SP1
Cubase Pro 8.0.40 Build 623 (64 bit)