Fix unknown capacity usb drive

A USB drive showing “unknown capacity” might be suffering from file system corruption, partition issues, or even firmware damage. Here’s a step-by-step approach to diagnose and potentially fix it:

Step 1: Basic Checks

• Try a Different Port or Computer: Rule out port-specific issues.

• Scan for Malware: Sometimes malicious software corrupts the drive’s structure.

Step 2: Use Disk Management (Windows)

1. Press Win + X → choose Disk Management.

2. Locate the USB drive (check for “Unallocated” or missing size).

3. If shown as “Unallocated”:

   • Right-click → New Simple Volume.

   • Format as exFAT or NTFS, depending on use case.

Step 3: Use Command Prompt Tools

1. Open cmd as Administrator.

2. Run:

    

   diskpart
   list disk
   select disk [your disk number]
   clean
   create partition primary
   format fs=exfat quick
   assign
   

   Note: “clean” will erase all data on the drive.

Step 4: Try Third-Party Recovery Tools

If Windows can’t fix it, try:

• MiniTool Partition Wizard

• EaseUS Partition Master

• HP USB Disk Storage Format Tool

These can repair partition tables or reinitialize the disk.

If It Still Doesn’t Work:

• The USB might be physically damaged or counterfeit (some fake drives report massive capacity but can’t store data correctly).

• You could try checking it with H2testw (tool to verify real capacity).

• Or consider replacing it—especially if critical errors keep appearing.