What to do?
On the edge of the SD card on the end of the card with the contacts but on the opposite side from the nipped off corner, is a slide switch (see Image below). It is normally in the position nearest to the edge connectors. In that position, it allows any device to read from and write to the card. That's where it must be while in the CPAP machine.
If you slide that little switch away from the edge connectors, that only allows a device to read from the card but not to write. For safety purposes, each time you remove the card from the CPAP so that you can read the data, just move the little switch to the LOCK position, read the card, and then move it back to the UNLOCK position before replacing it back into the CPAP device. All will be well, your ResMed CPAP will love you, your computer won't care, and life will be good.
