E3 Printer "File format error"

I've been fighting with this error over the last few days struggling to figure why it's happening. I'll upload a .gcode file into a USB drive that was exported via Simplify3D and attempt to print it, but upon clicking the triangle shaped print button next to the file name or the print icon located between delete and copy, I'll be prompted with the "File format error". I've used the same process in the past to upload files for print and it's worked without any trouble. Even preexisting .gcode files work fine and print without problem, but I now find myself unable to upload new prints to the printer.