[Reithal]

You didn't answer Mike's question about whether the audio files are on an SD card - some SD cards are flakey

Geoff

I'M sorry, but how could I find this? 
I found just this:  C:\Users\janba\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState

And it is my local disc

[otnt]

You didn't answer Mike's question about whether the audio files are on an SD card - some SD cards are flakey

Geoff

Jan did answer, posted the path:
C:\Users\janba\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState

Which means it's on the main storage disk.
I think it's more about compatibility of different Bluetooth protocols.