1. Download the Lexar tool and extract to your PC from following link
2. Click on the ‘Non-Active’ radio button at the bottom of the window
3. Now click on the ‘Format’ button
4. Remove and insert back of your Flash drive
5. Go back to disc management and reformat the flash drive again and you will get the whole space again
If BootIt refuses to work do this:
Right click “computer” and click manage. Click “disk management”, then click your drive. Right click the affected partition (or whatever that empty space is) and click properties. Then go to the “tools” tab, and under “error checking” click “check now”. After it does this, reformat the drive, and you should have all of your storage back.