Repetier Host 1.6.2 won't upload external files to SD card
I think there's a bug in Repetier Host.
It looks like Repetier Host ignores the external file option (in the SD card upload popup) and always writes the file it has (previously uploaded via the LOAD button on the main page) to the SD card.
If it a file hasn't yet been uploaded then the SD card gets a zero length file.
See the following for more details: https://forum.repetier.com/discussion/2470/problems-uploading-external-file-to-sd-card-marlin#latest