In any case:
ANY FILE or DIRECTORY added to the ResMed SDCard (at the root at least) will stop the S9 from using the card.
The solution is simple: Erase any extra files created by either the system or yourself.
Hidden and locked files can be removed without much trouble (see previous discussion) from withing the operating system.
Personally, I prefer using the command prompt for this purpose.
Sleep study AHI: 49 RDI: 60 -- APAP 10-11 w/AHI: 1.5 avg for 7-days (up due likely to hip replacement recovery)
"We can all breathe together or we will all suffocate alone."