My sdcard's content (Android ver 5.1) is missing after the phone sleeps or the screen turns off. I tried using sd repair in Windows and checking its file system if there were errors but no one found. I also tried to use the sdcard in the other phone but the problem does not occur so I think the problem might be in my android phone.I also notice that thr stock file manager also shows the Sd card in the top and the phone storage is next to it. Other file manager treated my sd card as "internal storage". Can anyone tell me how to fix this issue? Thank you.