ResMedS9 won't read card

[LyndaV]

I borrowed a ResMed S9 with a card in it.  I loaded SleepHead and read my stats for one night.  When I put the card back in the machine, it asked me if I wanted to delete data.  I said no and it told me to remove the card.  The machine still worked, but no stats loaded this morning.  I just discovered the lock/unlock knob on the card - which way should it be in the machine?  Somewhere it said it has to be locked before going into the computer to read.  I also read that the S9 will reject SD cards with any extra files written on them.  But this is a ResMed card!  I tried using a brand new sd card but the machine told me it was an illegal card.  Help!

[Crimson Nape]

Resmed just buys SD cards in bulk and puts their name on them.  Other than their high price, there is nothing special about them.  You will need to have the card in the Write Enabled (unlocked) condition while it is in the S9 and Write Protected (locked) prior to inserting it into your computer.   Also, some of the newer low cost card readers do not have the micro switch installed in the unit.  This means that even if you have it write-protected, it may not stop it from having the system files written by the PC.

To be safe you may wish to download and use the following script. It will turn off(or back on) this feature on your PC.
Prevent SysVol Info Write



Good luck!

[DeepBreathing]

Just to expand on what Crimson Nape said. Whenever Windows sees a new disk drive (and cards are regarded as drives) it will try to write some identifying (system volume) files on it. Most machines don't mind this, but the S9 will throw a hissy fit, as you have seen. Once these system volumes files have been written to a card the S9 won't work with it unless the card is reformatted, which will lose your existing data. This is not a big deal if you have the data backed-up to your computer before you let the machine do the reformat.

[Sleeprider]

I added the script to the SD card wiki and Beginners Guide to Sleepyhead.