MS Pro Duo Dual slot adapter only reads 1 at a time =(

[loitran510]

Hi,
My MS Pro Duo Dual slot adapter can read up to two at a time (combinded) but it only reads the one on the first slot. Each of my Micro SD is 8gb, so it should be around 16gb, but its only around 7gb. I also have another set of 8gb micro SD and they worked together, but this set only reads 1. any help? Also its a Samsung micro SD.

Thanks

[Funkstar]

Do the Micro SD cards need to be formatted and partitioned to be as one drive while inserted in the adapter?

I've never used one of those, so cannot speak from experience in any way.