All had been running well, until recently the drive letter assigned to the SD reader changed from E: to F:, and the XCOPY failed.
So far, the batch file is just a single line, running XCOPY from a specific network location to a specific local drive. Specifically, when the scheduled Windows backup completes, that triggers an event which runs a batch file to copy the contents of the backup folder (which contains more than the backup of that particular computer) to the SD card.
I have a computer running Windows 7 with a built-in SD card reader.