Windows 11's upcoming 24H2 update has introduced an unexpected storage headache for users, with reports of 9GB of undeletable files appearing on systems. This puzzling issue has sparked discussions among Windows enthusiasts and raised concerns about Microsoft's new "checkpoint" update system.

The 9GB Mystery: What's Happening?

Users testing Windows 11 24H2 builds have discovered approximately 9GB of system files that can't be removed through conventional methods. These files appear in the following locations:

  • C:\$WINDOWS.~BT\Sources\Panther
  • C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Windows\DeliveryOptimization

Attempts to delete these files through Disk Cleanup or manual deletion result in permission errors, even when using administrator privileges. The files persist through reboots and remain stubbornly present on the system.

Microsoft's Checkpoint Update System: The Culprit?

This issue appears related to Microsoft's new "checkpoint" cumulative update mechanism introduced in Windows 11 24H2. The system creates:

  1. A complete system snapshot before updates
  2. Extensive logging of the update process
  3. Backup files for potential rollback scenarios

While designed to improve update reliability, this approach comes with significant storage overhead. The 9GB files seem to be:

  • Update installation logs
  • System state backups
  • Temporary installation files
  • Delivery Optimization cache

Why Can't These Files Be Deleted?

Microsoft has implemented strict protections around these files because:

  1. They're considered critical for system recovery
  2. They may be needed for future updates
  3. The checkpoint system maintains active handles to these files
  4. Special system permissions prevent modification

Workarounds and Solutions

While Microsoft hasn't officially addressed this issue yet, some users have reported success with:

1. Using the Storage Sense Feature

  • Go to Settings > System > Storage
  • Enable Storage Sense
  • Configure to clean up temporary files automatically

2. Manual Cleanup via Command Prompt 

takeown /f "C:\$WINDOWS.~BT\*" /r /d y
icacls "C:\$WINDOWS.~BT\*" /grant administrators:F /t
rmdir /s /q "C:\$WINDOWS.~BT"

(Use with caution - may affect system stability)

3. Waiting for Microsoft's Official Fix

Given the system-critical nature of these files, waiting for an official solution may be safest.

The Bigger Picture: Storage Management in Windows 11

This issue highlights broader challenges with Windows storage management:

  • Modern Windows installations require increasing disk space
  • System files are becoming more opaque to users
  • Update mechanisms are prioritizing reliability over storage efficiency

Microsoft will need to balance these competing priorities as Windows evolves.

What Users Should Do Now

  1. Monitor your storage space - Keep an eye on system drive capacity
  2. Avoid aggressive manual deletions - Some files are genuinely needed
  3. Report the issue - Use Feedback Hub to bring it to Microsoft's attention
  4. Consider storage upgrades - Modern Windows works best with ample free space

Looking Ahead: Microsoft's Response

As the 24H2 update approaches general availability, we expect Microsoft to either:

  • Provide official cleanup tools
  • Reduce the storage footprint
  • Document the files' purpose more clearly

Until then, users should approach these mysterious 9GB files with caution, understanding they're part of Microsoft's evolving update infrastructure designed to keep systems stable and recoverable.