Bob5151F, in my 2005 Ovation 2 (G1000 non WAAS 0401.30) I tried various SanDisk 4GB and 8GB SD cards that I had bought on Amazon and eBay for nav data updates. Some worked and some didn't, so I suspected the card formatting might be an issue. After some experimentation I found the SD card formatter from the Secure Digital Association (SDA), available for Windows and iOS. When I format the SD card with this program my G1000 recognizes the card. When I format the same card with Windows 10 (FAT32) it doesn't. I think the SDA formatter follows the SDA spec and Windows doesn't. I haven't made