Recovering unallocated space of a USB flash drive.

Let’s remove unallocated space. First of all run Windows command line and type diskpart in the command prompt. Windows will ask you for Administrator permissions to run the tool. Then run list disk command to find your USB flash disk’s number. It should be the same as disk’s number in Computer Management tool. It was 1 in my case. Next you should chose the disk to work with. Type select disk <disk number> command, e.g.select disk 1. The next step is to clean all volumes and partitions on the disk. Use clean command to do that. The last step is to create a primary partition. You can do that using create partition primary command. That’s all. You should be able to format your flash disk now.

This is how I removed unallocated space on my machine:

Microsoft DiskPart version 6.2.9200

Copyright (C) 1999-2012 Microsoft Corporation.
On computer: COMPUTER

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          298 GB      0 B
  Disk 1    Online         7509 MB  6619 MB

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> clean

DiskPart succeeded in cleaning the disk.

DISKPART> create partition primary

DiskPart succeeded in creating the specified partition.

DISKPART> exit