Drive shows the wrong storage capacity

Symptoms

• 32GB drive shows as 8GB or less in File Explorer
• Files larger than the shown capacity refuse to copy, or copies get corrupted
• Drive was bought from an unfamiliar or third-party seller
• Formatting doesn't restore the advertised capacity

Likely causes

• CommonCounterfeit drive with fake capacity firmwareCheap fake drives report a large size but only actually store a fraction of it.
• PossibleDrive has hidden or unallocated partitions taking up spaceA previous use (like a bootable installer) can leave partitions behind.
• PossibleDrive formatted with a file system that shows different usable spaceSome file systems reserve overhead space, though rarely this much.
• PossibleManufacturer capacity uses decimal gigabytes vs. Windows' binary calculationThis normally only causes a small, expected difference, not a drastic one.

What to do

1. Open Disk Management and look at the full disk map for hidden or unallocated partitions.
2. If partitions are taking space, back up any needed data, then delete and recreate a single partition.
3. Use a manufacturer capacity-check tool (like H2testw or F3) to verify whether the drive is a counterfeit with fake capacity.
4. If a capacity test shows the drive is fake, stop using it for important data since it will silently corrupt files past its real capacity.
5. If bought online, request a refund or replacement citing the failed capacity test.
6. If it's a genuine drive with only a small discrepancy, this is normal and not a fault.

Tools and parts

• Capacity verification tool (e.g. H2testw, F3)

When to call a pro

A confirmed counterfeit drive can't be fixed; return it and buy from a reputable retailer instead.

Safety