Paul, you got good advice on returning the Packs that are missing. However, for your registrations to work properly, you need to install Packs in the same order as before deleting. This is determined by the LSB position.
This is not mentioned in the video, and it is very important when you have install more than one Pack.
[video:youtube]
https://youtu.be/PmqB_FtxapQ?t=115[/video]
Now that I did not know. Installing Packs in the same order they were deleted can be a guessing game. Yamaha needs a way to save a backup of Expansion Packs so that they can be reloaded in the correct order for registrations to work properly.
I always assumed that registrations were a direct link to styles, sounds, DSP's etc. and would work as long as those styles, sounds, DSP's, etc were available to link to a USB or user memory files. Why should it make any difference
when those style packs were reloaded?