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.

