If I saw the answer in earlier posts, I didn't recognize it BTW. Thanks for your patience.
I'm able to see and play Sib and VDL on a couple of files, so I think I'm looking for a simple cure.
Sibelius 7.1.3 build 77
S7S Soundset 7.1a
VDL 2.5.5
VDL Soundset 7.0a
Windows 7
I think I have the correct instances loaded in configuration but if I try to add instruments I don't see VDL listed. If I bring up certain previous files, I see the VDL option and everything works ok.
Any advice? Thanks much. Screenshot attached
Kent