i cannot delete multiple files on file explorer

i am using 5.0.1 stock rom sense 6 and when i go into the file manager and i want to delete something or to move 2 files or more it say's

please select your sd card first i select my sd card and then it says documents has stopped mpla mpla and at the at bottom it say's Authorization it fails

does anyone had this before ? on other custom rom's i didn't had this problem and anyway it wasn't asking for to choose my sd card

Cheers i always appriciate your help