Resmed S9 won't start up with SD card

I removed my SD card to plug it into my computer to use with Oscar. (Yes, I moved the lock switch to Lock before inserting it). Now when I try to plug the SDCARD back into my S9, I get an error message asking me if I want to format it, but even if I say yes, nothing happens. My machine won't turn on by switch or auto start, until I remove the SD card. It runs fine without it, but I can't track my data.

How to fix?

What your describing is exactly the behavior that an S9 does when a foreign file is written on the SD Card and there is nothing you can do to use that SD Card without reformatting it.

Although, all your data will be wiped from the card, it's been imported into OSCAR on your computer so you should be good.

This happens with S9 in one of two circumstances, when the write protect tab hasn't been set, or when SD Card drive is being used that doesn't respect the state of the write protect switch.