USB Drive Not Showing Full Capacity After Making It Bootable
Your 64 GB pendrive suddenly shows 14 GB. The space is almost never lost — here is where it hides, and how to get it back with or without the boot setup.
✍️ Technical Anshu💽 Bootable USB Toolkit⏱️ 8 minute read
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Few sights panic a new toolkit builder like this: the 64 GB pendrive now shows as a small drive, and most of it seems to have vanished after making it bootable. Nothing vanished. The capacity is sitting in partitions Explorer does not show you, or in unallocated space an image writer left behind — plus one small, permanent illusion in how GB are counted. Here is how to see the whole drive and claim every part of it back, in whichever form you want.
Disk Management — where did the rest of the 64 GB go
💽 Disk 2 · (E:) — 14.4 GB exFAT · the only part Explorer shows as your driveIn use
⬛ Unallocated — 45.1 GB · written off by a small boot imageRecoverable
🔒 VTOYEFI — 32 MB FAT · the boot partitionNormal
☝️ The space is almost never gone — it is sitting in another partition, or unallocated, where Explorer does not look
1
Understand Why Bootable Drives Look Smaller
A bootable USB is partitioned. Windows Explorer shows you partitions, not the physical drive — so a 64 GB pendrive can appear as a small drive letter while the rest sits elsewhere
Tools that write one disk image directly (including Windows media creation in some modes) size the partition to the image — a 5 GB image can leave a 64 GB drive showing about 5–14 GB, with the remainder unallocated
And one part of the "loss" is fake: a "64 GB" drive honestly holds about 58.6 GB in Windows numbers (manufacturers count GB differently), plus a few hundred MB of partitions. That part is normal on every drive ever sold
2
See the Whole Drive in Disk Management
Press Windows + X and open Disk Management (or run diskmgmt.msc)
Find your USB by total size in the bottom panel — you will see every partition and any black-barred Unallocated space
Now decide what you actually want: the space back as one normal pendrive (Fix 3), or the space added to your working toolkit (Fix 4)
3
Get the Full Capacity Back as a Normal Pendrive
This removes the boot setup completely — do it when the drive is retiring from toolkit duty. Back up any files first.
In Disk Management, right-click each partition of the USB and choose Delete Volume, until the whole drive is one Unallocated bar
Right-click it → New Simple Volume → use the full size → format exFAT → Finish. The drive now shows its full honest capacity
The Command Prompt route does the same: run diskpart, then list disk, select disk N (triple-check N by size), clean, create partition primary, format fs=exfat quick, assign
4
Keep the Boot Setup and Claim Only the Free Space
If the missing space shows as Unallocated and your boot partition works, right-click the unallocated area → New Simple Volume → format exFAT and label it DATA. You gain a second data drive letter and lose nothing
If instead the data partition itself is small with no unallocated space behind it, the image was written partition-sized — there is nothing to claim. Rebuild the drive with a multi-boot tool and copy your files back in; the whole capacity becomes usable at once
Either way, never delete the small VTOYEFI partition while the drive still has toolkit duty — that 32 MB is what makes it boot
⛔ DiskPart clean is instant and unforgiving — it wipes whichever disk is selected, no recycle bin, no undo. Disconnect every other external drive, and confirm the disk number by size twice before pressing Enter. More PCs have been hurt by the right command on the wrong disk than by any virus.
🎥 Watch the Complete Build in the Full Video
Making the USB bootable, adding portable software and arranging the ISO files — the entire process is shown live in the video.
No — 58.6 GB is the honest, full size of a "64 GB" drive in Windows. Manufacturers count a GB as 1,000,000,000 bytes; Windows counts 1,073,741,824 bytes, so the displayed number is always about 7% smaller, before a few MB of partitions. Worry only when a drive shows dramatically less, like half — then check partitions in Disk Management, and test suspicious drives with H2testw for fake capacity.
Will DiskPart clean remove the boot menu permanently?
Yes. Clean erases the drive's partition table, including the boot partition — that is precisely its job when you want a plain pendrive back. The drive is not damaged; you can make it bootable again any time by reinstalling your boot tool and copying your files back from the master backup.
Why does my PC show only one partition of the USB?
Very old Windows versions displayed only the first partition of removable drives. Windows 10 (from version 1703) and Windows 11 show all partitions of a USB drive in Explorer and Disk Management. If you see only one letter on a modern system, the other areas are usually unallocated space or the tiny boot partition without a letter — Disk Management reveals the full picture.
This guide is based on the Technical Anshu ultimate bootable USB video • Stuck on any step? Ask in the video comments — help is available there 🙏