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FAT memory sticks

This is just short item that may recover the use of old and discarded USB memory sticks. If you see any of the following messages when managing your USB memory sticks, they may be formated with the FATXX (File Allocation Table) format.

Cannot make directory entry – “Filename”

“Filename” – This filename is not valid.

Unable to create “New Folder”. Make sure the disk is not full or read-only.

If you are interested in why this problem occurs you can research it yourselves – it is sufficient to say here that the FAT format has some short commings which is why it is being superceeded by NTFS. However some hardware vendors seem reluctant to support the newer technology.


If you can read the memory stick, backup all the data on it to location on your hard drive.

If you need the memory stick to stay in FAT format so that, say, your PS3 games machine can read it then you’ll need to remove some of the files in the root directory and place them in folders. You need to reduce the number of files in the root directory of the memory stick as the number of ‘entries’ that can be stored has run out. So no more files or folders can be created even though there is plenty of space on the drive.

If you don’t need the memory stick to stay in FAT format then format it as NTFS. Do this by ensuring nothing is referencing the memory stick (such is Windows Explorer) then:

Create a command prompt (Start – Type CMD in search – then double clicking cmd.exe in the results list)

Type F: followed by return (where F is the letter for your USB stick)

Type FORMAT F: /FS:NTFS, then follow instructions.

You can then copy all your files back to the USB stick and carry on using it.

Hope thats helpfull – you can find out lots more about FAT based formating and its limitations (such as max file size) by searching for FAT12, FAT16, etc