[Equipment] Adventures with my corrupted SD card

[Slick7533]

After 3 weeks and 3 occasions of successful data captures of my sleep SD card on my Windows 7 Professional computer - after the fourth download the card was no longer able to be read by my CPAP machine when I put it back in.

I was careful each time to turn off the power and lock the card but it still got corrupted. I suspect the cheap card reader I used may have done something.

There is no utility in the Respironics machine to reset or troubleshoot the SD card so I had to explore other options. I really did not want to go back to my provider to pay 10 times the price for a standard SD card.

Anyway, I noticed when I looked at the Windows explorer that the file structure in the SD card looked just like any other data storage device on a Windows machine so I figured I had nothing to lose by reformatting the SD card and trying to start over. Now all I had to do was figure out how to reformat an SD card and hope it worked

Before the corruption, there was a folder visible that looked exactly like this:

P-Series\

After corruption, the folder looked like this:

P-S#*+êª

Clearly a problem.

In that folder is where the actual data is written in about a dozen separate files with numeric names. I had seen them before but they were no longer visible or accessible at all following the corruption even though the card still reported over 1 gigabyte of data on it

After some research I discovered the SD Formatter Download from the SD Association.

https://www.sdcard.org/

It's completely free and they have documentation and it's pretty easy to set up and run.

I downloaded it, ran it at the least comprehensive (basic) level and all the gobbledygook on the card was gone.

With my fingers crossed I recreated the directory 'P-Series\' and placed the card back in my CPAP machine.

It has been happily recording data ever since. All is well again in SD Card land.

If you are a little bit comfortable with computers, this is not hard to do. I hope you'll never need this procedure, but here it is if you do. Good luck and good sleep

Cheers

[justMongo]

Just about any SD card will work. With the possible exception of SDHC cards.
ResMed uses a 2GB speed class 2 card.

You couldn't find it in "my Computer" -- right click -- and format?

[Slick7533]

Dang, I didn't realize Windows had that built in now. It even supports different file systems and allocation units. I'm going to have to experiment with it. Looks like it might have even more options for compatibility than the downloaded utility

[archangle]

The windows format program usually works just fine for CPAP SD cards.

The special SD card formatter is mostly for the copy protection BS for music downloads. I don't know if anyone actually uses that copy protection garbage these days anyway. Note that "Secure" in "Secure Digital" is "security" for the record companies from you being able to access the data on the card, not "security" for you, the owner of the card.

Pretty much any SD or SDHC card will work on ResMed or PRS1 machines, although occasionally someone will report that SDHC won't work for them. The machine won't use the extra space on cards larger than 2 GB, but they usually work.

I recommend simply replacing the card if you have any problems, especially after trying a reformat one time. They're cheap enough to not worry about. In my experience all SD cards are fairly unreliable, and you just need to replace them when they go bad.