I recently bought a 4GB microSDHC card and had serious trouble reading the card using my laptop's built-in card reader under Windows Vista w/ SP1. The card reader had been able to read other cards of less capacity, including a 1GB card, just fine. Looking around on the web made it apparent that a LOT of people had the same issue when attempting to read cards above 2GB. It took a lot of reading through various forum posts on the subject before I finally got it working with the 4GB card.

The built-in card reader in my Acer Aspire 5673WLMi uses the Texas Instruments PCIxx12 Integrated FlashMedia Controller, which is a device found on a lot of laptops of various different models and brands. The latest driver version for the device currently issued by Acer, and most other manufacturers, is versioned 2.0.0.6. The two main solutions proposed on the forums is 1) an install/upgrade of the existing driver manually without using the installer software, and 2) registry hacks that supposedly fix the problem. Neither of these worked for me, though the forums postings indicate these "fixes" worked for many people.

I spent the better part of a day reading and checking various proposed fixes and, in the end, all it took was for the recent version 2.0.0.7B driver found on the HP Customer Care website to be installed...

Anyway, I thought I'd reiterate the solution in case it helps someone else...