hi, i have a 4 channel mpeg4 dvr and when i insert the usb at the front a message comes up saying usb connected, then i go through the menu onto usb backup, choose which camera, the start time end times etc and then when i click start an error message apears - 'usb file system error'. i have connected the usb with my computer and it is already formatted in fat32 format, but i did it again just in case. it is a 16gb sandisk flash usb. i have also tried a 4gb usb. i do not know the company of my dvr but i recieved it as a package with the ganz cameras. i have looked at the userguide and is not much help. so any help from here is welcome, thanks