Hi Stephen,
Probably the best way to get help with your issue is by phone (Customer Support) as they can get the important information from you to answer your question.
You've posted in the S70XS/S90XS forum and since they have not been around for 12 years, you either have an S90 or an S90 ES.. The exact model will be important.
Also the media to which you backup your data. The S90 goes back to SmartMedia Card, while the S90ES used USB drives.

If an S90 you should verify the SmartMedia card storage device - like all storage media they do have a life cycle. In either keyboard you are supposed to backup your settings to a File. This way you can easily restore your custom settings.

From your post it is not clear if when you mention a problem with storing whether that is to the removable media or to the internal memory. Either way the Customer Support folks will be able to tell you how to proceed.

Hope that helps. The Yamaha office nearest you can be found in the back of the Owner's Manual.
Let us know.

Thanks Bad Mister over the years I've used your advice many many times

I do have the s90 model and although I used the smart media storage cards in the past (for loading Vintage Keys and B's knees both of which I will have to try to load again) the trouble I'm having is just with the factory voices and the performance mode. I identify a performance and intitialize then use category search to find and the Add the voice and split setting to the performance I can't get it to store the new performance settings.

This has been so second nature to me over the years by being able to change voices in performances and store them even at live gigs that going back to the factory default and having to re buld them again is throwing me for a loop.

I have to be doing something wrong