Copy failed to USB flash drive with lots of space left
I tripped over a bit of DOS arcana this afternoon while setting up a new digital picture frame. I was copying a folder containing a few hundred JPEG files into a 1GB flash card using Windows XP, and eventually got an error dialog saying something like “can’t create file”. At first I thought perhaps it had run out of room, as I didn’t bother resizing the original image files before copying, but there were still a few hundred megabytes left after copying over 250 images to the flash card.
This reminded me of a problem I encountered in the stone ages of personal computing, which is a limitation of the original DOS file system. Basically, you can’t put too many files in the root directory of a DOS file system, as there is a fixed and relatively limited storage space assigned to it when the file system is created. If you want to put hundreds of files on a DOS16 file system, you need to use subdirectories. The DOS16 file system is widely used by many flash-based devices including digital cameras, music players, and USB sticks, even though it’s rarely used by desktop systems today. The Windows XP and Vista error messages for the full DOS root directory problem are cryptic at best, so I suspect others may come across this problem while setting up their digital picture frames and similar devices after the holidays.
If you are having a problem copying files onto your flash card or USB storage device, and it’s not actually full already, try creating a subdirectory or two to hold your files instead of copying them to the root directory.