Unhappy [Q] [Alps n9500 ] SD Card removed unexpectedly

i bought mtk 6589 n9500 3 months ago
http://forum.xda-developers.com/show....php?t=2276085

and i have a problem, SD Card removed unexpectedly

i searched google and tried format SDcard, factory reset , switch another SD, but no resolt.

this error appear every day..i think is a system bug..

how can i fix it?

phone is rooted..

sorry for poor english..