I had a strange experience when I had a corrupt Kingston 4gb micro SDHC card which worked fine for about 3 weeks. I had never taken it out of the N810 only using the USB connector. Then a few days ago I was trying to install KDE so I used a Sandisk Micro- SD adapter. XP would not reconnect the card and then attempting to put it back into the N810 resulted in "Corrupt Card" message. I tried a few different things but neither tablet, XP or Ubuntu was able to see the card. Eventually out of all options I started looking at return options since the card has a lifetime warranty and on a whim while emailing support at Kingston, I put the card into my N75 which isn't even compatible with SDHC. That device at least recognized a card but delivered the corrupt card message too and would not format. I then placed the card back in the N810 and voila it read the card and then plugged in via USB the XP machine read the card.

Anyway I have no idea what the issue was but regardless thats pretty unreliable I will be careful to do backups more often.