This article will show you how to format your hard drive so you can use it with your Xbox 360 as an additional storage for your photos and music, etc.
For this, only a Western Digital hard drive with a capacity of only 80GB and 250GB is suitable.
Steps

Step 1. In this process, your hard drive will be formatted, so back up all your files to another hard drive, laptop, or be prepared to lose everything on your hard drive

Step 2. After you've made your backups, connect your hard drive to your Xbox 360, then go to My Xbox / System Preferences / Storage
If an option titled "USB Mass Storage Device" appears, please skip to step 8.

Step 3. This may only work on Windows 7
Connect the hard drive to your laptop. Open the Start menu, right-click on "My Computer" and select "Manage".

Step 4. In the "Computer Management" section, select "Mass Storage / Disk Management"

Step 5. Find your external hard drive, right click and select 'Format'

Step 6. Change the file system to 'exFAT', select "OK" and then select "Continue" on the next screen

Step 7. Reconnect the hard drive to the Xbox 360, then go to My Xbox / System Preferences / Memory

Step 8. Select "USB Mass Storage Device / Configure Now", then accept the warning

Step 9. After formatting is complete, a warning window will appear, click "OK"

Step 10. Now on the "Storage Devices" screen you should see a new option "Memory Block"
This indicates that the formatting was successful.

Step 11. Unplug your hard drive and then plug it into your laptop, download your media files (this will make sure the file types are compatible), plug it into your Xbox 360

Step 12. Your selected media should not appear in the "Portable" section of your video / music / photo library
Warnings
- This method uses up to 16GB of hard drive, if you don't want to waste that amount of space, this guide is not for you.
- Formatting the hard drive will erase all data. Backups must be done first!
- This guide was first created with a Windows 7 laptop and Xbox 360 using the latest firmware and dashboard on 2010-20-12.