Home > Questions

How to restore USB flash drive back to full capacity on Mac? Help!

Hey everyone, I recently bought a genuine 256GB SanDisk USB drive. Initially, it showed the full capacity of 256GB even after reformatting to ExFAT. However, after using it to create a bootable drive, I was shocked to find that the capacity had mysteriously reduced to only 6GB. I tried using Disk Utility to erase the drive completely, but it still remained at 6GB. The partition icon is now greyed out and unusable. I'm stuck and unsure how to reformat the drive and regain its original capacity. It was quite an expensive USB drive, so any ideas or suggestions would be greatly appreciated. Thanks in advance for your assistance!

Best Answered by

iBoysoft author Jenny Zeng

Jenny Zeng

Answered on Monday, April 29, 2024

It seems that your USB drive's size reduced after making it a bootable drive and you are unable to reformat it to regain its full capacity. I suspect you're not formatting the drive correctly. The following is the correct way to do it.

How to restore a USB drive back to full capacity on Mac:

  1. Open Disk Utility.
  2. Click View > Show All Devices to reveal the physical drive.
  3. Select your USB drive that's not showing full capacity from the left side.
  4. Click the Erase button.
  5. Type a name for your drive.
  6. Choose a format for it. (Mac OS Extended or APFS if you only need to use it on your Mac.)
  7. Select GUID Partiiton Map as scheme.
  8. Click Erase.
  9. Wait for the erase process to complete.

After that, your USB drive should show its full capacity.


People Also Ask

Read More Questions

Read More Advice From iBoysoft's Computer Experts

Erreur de non prise en charge du formatage par NTFS dans le Terminal Mac

Le formatage n'est pas pris en charge par : NTFS Erreur dans le terminal Mac?

Impossible de formater en NTFS dans Terminal car 'Le formatage n'est pas pris en charge par : NTFS ntfs Système de fichiers Windows NT (NTFS)'? Apprenez comment formater n'importe quel lecteur en NTFS sur macOS.

Astuces NTFS pour Mac

Cómo reformatear discos duros externos en Mac

¿Cómo reformatear HDD/SSD para Mac y PC sin perder datos?

Aprende cómo reformatear un HDD o SSD para Mac, de Mac a PC, o para ambos Mac y PC, y cómo hacer que tu disco duro externo sea compatible con Mac y PC sin reformatear.

format drive to NTFS on Mac

How to Format NTFS on Mac & Format to NTFS on Mac?

Learn how to format NTFS drive on Mac and format drive to NTFS on Mac using Terminal, Disk Utility and NTFS formatter for Mac.

NTFS for Mac Tips