I thought I was going mad today. I wanted to print some rails for the FT817 and I already had the sliced files on the SD card in the 3D printer. I selected the first (there are two, one is a mirror of the other) and told it to print. Nothing. Reset the printer and tried again. Nothing. Opening the SD card on the Mac showed the file to be 0 bytes, which is certainly was not as I had printed it before. Ok, copy it again and try again. Nothing!
Right. Delete all the files on the SD card – I have them all on the Mac anyway. Copy just the files for the rails across and try again.
Looking at the SD card via a terminal window – I must admit to be my favourite UI – it was full of all sorts of junk. Going duff perhaps? Ok, use a recycled 8Gb micro-SD in a holder, delete all the files currently on it, copy the rails across and try that. Ah, the files did not delete so it’s full of old junk and I can’t spot the files to print. Back to the Mac. Tried 3 times with different holders to delete all the files on this micro-SD and each time unmounting and re-mounting it showed they were all still there. That micro-SD is in the bin now.
Right! Use another micro-SD, delete all the old files, copy just the two gcode files across and …. it’s printing!