Halion5 instruments

When using Halion 5 in standalone mode to checkout sounds etc, the window with
the columns :category:sub category:style: character, shows all the available sounds in media bay
and the dropdown ‘All Instruments Sets’ is selected. Without warning the instruments
selected in the upper window stop being displayed in the lower window, so I cant move
anything to the slot rack. In Cubase 6, when accesing Halion 5 as a VST instrument, the problem persists.
I make a WIN7 system image backup every 2 weeks, and when I reload the image, Halion 5 works fine for
another few days, and then it reverts to the above problem. I use win7, Cubase 6 ,Wavelab 7, on
a X5 cpu.
Any suggestions.