Default Tipo don't scan ext_sd

Hi

My Xperia Tipo don't scan my sdhc 16gb class10 card. It all is in music and when I plug it to phone and launch, the phone has 0mb ram left and music don't appear in Apollo, which I use to listening to music. The phone is very laggy and apps crashes when SD card is "scanning". I will be very thankful for every help.