Some USB drive will see small amount of space that is unallocated.. So i would like to tell you how to fix this as below with command wind window PC. First we start CMD and try Diskpart you will see like picture below and Please try following Command to fix this issue.
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
After you can reinsert your USB again and Try to Format that USB. good luck.
