Check the tiny "Lock" switch on the side of the SD card. If it's pushed down, the card may not mount properly on some systems.
If you are using a very old computer (pre-2008), the internal reader might only support standard SD cards (up to 2GB). In this case, no driver can fix it; you will need a cheap USB SDHC/SDXC Adapter . 4. Direct Download Links (Common Hardware) draiver dlia sdhc skachat
If you know your hardware brand, these are the most common official sources: Realtek Card Reader Drivers Intel Chipset Software Check the tiny "Lock" switch on the side of the SD card
Here is a quick guide on how to get your card reader working again. 1. The "Hidden" Truth About SDHC Drivers no driver can fix it