Yep that would be my guess too. But since I am reading it with my Pic, it has to be stored on the SD chip somewhere correct? I mean on on earth could the SD chip generate those messages? My Pic software that reads the SD certainly is not doing it.The "Invalid Sector" would be an OS message, like the card isn't responding correctly.
What I am trying to find is a one for one. I has hoping to find Invalid whatever using the card reader to make sure I am reading the sector is what I think I am reading. For example, if I found some kind of signature with the Pic like "Invalid" found on sector zero but found "Invalid" on sector 10 using the hexeditor on my pc, it probably means I am not reading the sectors correctly.
What I find strange is I have yet to find FAT32 on my SD chip using the Pic but I can see it with the HexEditor on the PC.
What I think you are supposed to do is to take the sector # and multiple by 512 and use that to read the SD Sector. Though I am still not 100% sure of that. I might try not multiplying and see what results I get.
But you would think I would at least be reading sector 0 the same.