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I play around a lot with my USB flash drives. They’re useful for so many things beyond just transferring files between devices. For example, you can use a USB drive to lock and unlock your computer as well as carry around portable apps everywhere you go.
As for me, I mostly use them as bootable drives for ISO files, which comes in handy when I want to try new flavors of Linux or turn a bricked laptop back into a Windows machine.
But I recently ran into a weird problem: I’m not sure how, but my 4 GB USB drive was suddenly showing up as a 100 MB USB drive. I’d lost a huge chunk of my drive’s storage capacity! Fortunately I found a fix, and if this has happened to you, rest assured that the fix is surprisingly simple.
As it turns out, the USB drive’s partitions had been tampered with, leaving most of the drive “unallocated” and inaccessible. That’s likely what happened to your drive. To fix this, we’ll just reset the partitions on the drive and “reallocate” all of the space as a new, single partition.
Before going ahead, back up your data! The following steps will completely wipe your drive. And make sure you pay attention to step 4 as you don’t want to accidentally wipe the wrong one!
- In the Start Menu, search for and launch diskpart.
- Type list disk to see all current disk volumes on your system.
- Plug in your USB drive and type list disk again. Note the newly listed volume.
- Type select disk # where # corresponds to your USB drive’s volume number.
- Type clean to wipe the volume of all partitions.
- Type create partition primary to make a new partition with all unallocated space.
- Type exit to finish.
If done correctly, your USB drive should be back to normal: a single partition with all of the space on the drive properly allocated and used. No more lost space!
Unable to reformat the drive? It might be write protected—here’s how to format a write-protected USB drive.