Repairing broken USB partition tables

While trying to use my 16GB USB flash drive as a raw-disk for VMware, I managed to corrupt the partition table. This rendered the drive useless for data storage. As none of the information contained on the drive was useful, it seemed that the best solution was a straightforward partition table wipe and rebuild. This can be difficult on Windows as Control Panel->Administrative Tools->Disk Management does not allow the deletion of the primary partition.

Many Googl’d solutions involved rebooting with one repair/installation disk or another, however I’ve found a quicker way…

The Fix

  1. Download MbrFix. [Working mirror at time of writing.]
  2. Use mbrfix /drive <num> driveinfo to identify the USB flash drive. The <num> refers to the physical identifier. Start at zero and increment until one of them gives a size reading that matches; this is probably the correct drive.
  3. Use mbrfix /drive <num> clean and enter “y” to confirm partition deletion. WARNING: IF YOU DO THIS, DATA RECOVERY FROM THE DRIVE IS DIFFICULT, BE SURE YOU HAVE CHOSEN THE CORRECT DRIVE!
  4. Go to Control Panel->Administrative Tools->Disk Management and right-click on the unallocated space. Select create new partition and fill in the details.
  5. This has reset the drive with a healthy partition, you should find it has regained functionality!

One thought on “Repairing broken USB partition tables”

  1. I have the exact same problem with a 3gb flashdrive.
    I had no problem identifying the drive, as you write in pt.2. but when i try to run MbrFix /drive clean, to clear the partitions, I get as far at “are you sure (Y/N)” and when i press Y … it tells me “Function failed. Error 5: Access is denied.” — bummer!

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