Default USB storage issue

Guys recently I started using 32GB card with my MMX CHD and everything is working only for when I try to connect my mobile to PC for file transfer via usb storage I can see only two drive one of CD drive of mmx and other internal sd drive and I can see one more drive but it is not mounted which is my external sd drive when clicked on it, it asked to enter disk guys plz help.
Solution tried so far by me
1. I have erase external sd card in mobile itself.
2. Reset the entire phone.
3. Uninstalled the mmx driver on my PC and reinstalled it.

Current Device: Micromax Canvas HD A116
OS: Jelly Bean 4.2.1
ROM: Stock ROM
Previous Device: HTC HD2, Nokia 3230, Motorola C375