Claude Cowork Data Management Tool

Tools and guides for managing Claude Cowork's virtual disk (VHDX) and preventing C: drive space exhaustion.

🚨 Problem

Claude Cowork silently consumes several GB to tens of GB on your C: drive.

Claude Desktop is distributed as a Microsoft Store app (MSIX package), not a traditional Windows application. This means data is stored in a package-specific location that most users don't check.

When you use Cowork, it creates a virtual disk (VHDX file) using Virtual Machine Platform in:

C:\Users\<YourName>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Local\vm_bundles\

Note: The package folder is typically Claude_pzs8sxrjxfjjc for standard installations. If your folder name differs, adjust paths accordingly.

Most users don't notice until their C: drive runs out of space.

✨ Primary Solution: Move VHDX to Another Drive

Use move_claude_vmbundles script to relocate the VHDX to C:\ClaudeData\ (or any other drive).

Step-by-Step Instructions

Close Claude Desktop completely
- Quit from system tray
- Verify Claude.exe is not running in Task Manager
Run the script as Administrator:
```
move_claude_vmbundles.bat
```
- Moves vm_bundles/ to C:\ClaudeData\vm_bundles\
- Creates a junction point at the original location
- Sets proper AppContainer permissions
Launch Claude Desktop
- If Cowork doesn't work immediately, restart your PC
- Junction synchronization may require multiple reboots in some cases

What Gets Moved

Virtual disk files (VHDX) - the largest space consumer
All Cowork workspace data

🔄 PC Migration (Cross-PC Restore)

If you're migrating to a new PC, you need to preserve two critical folders:

Folder	Content
`vm_bundles/`	Virtual disk (VHDX) - your workspace files
`local-agent-mode-sessions/`	Session registry - conversation history

Migration Procedure

On Old PC:

Close Claude Desktop completely

Backup both folders simultaneously:

# Adjust backup destination as needed
robocopy 'C:\ClaudeData\vm_bundles' 'D:\Backup\vm_bundles' /E /COPY:DAT /R:1 /W:1

robocopy "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions" `
         'D:\Backup\sessions' /E /COPY:DAT /R:1 /W:1

On New PC:

Install Claude Desktop
Close Claude.exe completely
(Optional) Externalize VHDX to C:\ClaudeData:
```
move_claude_vmbundles.bat
```
- Skip this step if you want to keep VHDX in the default location
Restart PC
Launch Claude and create a dummy Cowork task
- This initializes the VHDX file structure
- Just create any simple task (e.g., "list files in Downloads")
Close Claude.exe completely

Restore backup using robocopy:

If you externalized (step 3):

robocopy 'D:\Backup\vm_bundles' 'C:\ClaudeData\vm_bundles' /MIR /COPY:DAT /R:1 /W:1

robocopy 'D:\Backup\sessions' "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions" `
         /MIR /COPY:DAT /R:1 /W:1

If you kept default location (skipped step 3):

robocopy 'D:\Backup\vm_bundles' "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Local\vm_bundles" /MIR /COPY:DAT /R:1 /W:1

robocopy 'D:\Backup\sessions' "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions" `
         /MIR /COPY:DAT /R:1 /W:1

Fix AppContainer permissions (Administrator PowerShell):
```
icacls C:\ClaudeData /grant '*S-1-15-2-1:(OI)(CI)F' /T
```
- If you kept default location, adjust path accordingly
Restart PC
Launch Claude
- If synchronization fails, restart PC again (may require multiple reboots)

What Gets Preserved

✅ All conversations and projects
✅ Authentication state
✅ Memory and preferences
✅ Workspace files

Verified Migration Paths:

Windows 10 LTSC ↔ Windows 11 25H2

⚠️ Critical Notes

Before Running Any Operations

Always close Claude Desktop completely
- Check system tray
- Verify in Task Manager that Claude.exe is not running

Backup Guidelines

Backup both folders at the exact same time
Never restore only one folder - they must be synchronized pairs
Restoring mismatched versions will cause session errors

System Requirements

Windows 10/11 Pro/Enterprise/Education
- Windows Home is NOT supported (lacks full Hyper-V)

Virtual Machine Platform must be enabled:

Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform

Administrator privileges required for all operations

Troubleshooting

Cowork doesn't work after migration:

Restart PC (may need 2-3 reboots for junction sync)
Verify both folders were restored
Check AppContainer permissions with icacls C:\ClaudeData

"Plan9 mount failed" error:

You're on Windows Home (unsupported)
Upgrade to Pro/Enterprise/Education

🔍 Why These Two Folders?

Through extensive cross-PC testing, we confirmed that only these two folders contain all Cowork data:

vm_bundles/
- Contains VHDX virtual disk files
- Stores all workspace files and execution environment
local-agent-mode-sessions/
- Registry mapping sessions to VMs
- Preserves conversation history

They must be treated as a synchronized pair - backing up or restoring only one will break the system.

📝 Files in This Repository

File	Purpose
`move_claude_vmbundles.bat`	Launcher (run this)
`move_claude_vmbundles.ps1`	Main externalization script
`README.md`	This guide

🔗 Additional Resources

Detailed Technical Article (Japanese) - In-depth verification process and findings
Issues and pull requests welcome!

📄 License

MIT License

Author: Hiroto Kozuki
Verified Environments: Windows 10 LTSC, Windows 11 25H2
Last Updated: April 2026

Claude Cowork Data Management Tool

Tools and guides for managing Claude Cowork's virtual disk (VHDX) and preventing C: drive space exhaustion.

🚨 Problem

Claude Cowork silently consumes several GB to tens of GB on your C: drive.

When you use Cowork, it creates a virtual disk (VHDX file) in:

C:\Users\<YourName>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Local\vm_bundles\

Most users don't notice until their C: drive runs out of space.

✨ Primary Solution: Move VHDX to Another Drive

Use move_claude_vmbundles script to relocate the VHDX to C:\ClaudeData\ (or any other drive).

Step-by-Step Instructions

Close Claude Desktop completely
- Quit from system tray
- Verify Claude.exe is not running in Task Manager
Run the script as Administrator:
```
move_claude_vmbundles.bat
```
- Moves vm_bundles/ to C:\ClaudeData\vm_bundles\
- Creates a junction point at the original location
- Sets proper AppContainer permissions
Launch Claude Desktop
- If Cowork doesn't work immediately, restart your PC
- Junction synchronization may require multiple reboots in some cases

What Gets Moved

Virtual disk files (VHDX) - the largest space consumer
All Cowork workspace data

🔄 PC Migration (Cross-PC Restore)

If you're migrating to a new PC, you need to preserve two critical folders:

Folder	Content
`vm_bundles/`	Virtual disk (VHDX) - your workspace files
`local-agent-mode-sessions/`	Session registry - conversation history

Migration Procedure

On Old PC:

Close Claude Desktop completely

Backup both folders simultaneously:

# Adjust backup destination as needed
robocopy 'C:\ClaudeData\vm_bundles' 'D:\Backup\vm_bundles' /E /COPY:DAT /R:1 /W:1

robocopy "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions" `
         'D:\Backup\sessions' /E /COPY:DAT /R:1 /W:1

On New PC:

Install Claude Desktop
Close Claude.exe completely
(Optional) Externalize VHDX to C:\ClaudeData:
```
move_claude_vmbundles.bat
```
- Skip this step if you want to keep VHDX in the default location
Restart PC
Launch Claude and create a dummy Cowork task
- This initializes the VHDX file structure
- Just create any simple task (e.g., "list files in Downloads")
Close Claude.exe completely

Restore backup using robocopy:

If you externalized (step 3):

robocopy 'D:\Backup\vm_bundles' 'C:\ClaudeData\vm_bundles' /MIR /COPY:DAT /R:1 /W:1

robocopy 'D:\Backup\sessions' "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions" `
         /MIR /COPY:DAT /R:1 /W:1

If you kept default location (skipped step 3):

robocopy 'D:\Backup\vm_bundles' "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Local\vm_bundles" /MIR /COPY:DAT /R:1 /W:1

robocopy 'D:\Backup\sessions' "$env:USERPROFILE\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions" `
         /MIR /COPY:DAT /R:1 /W:1

Fix AppContainer permissions (Administrator PowerShell):
```
icacls C:\ClaudeData /grant '*S-1-15-2-1:(OI)(CI)F' /T
```
- If you kept default location, adjust path accordingly
Restart PC
Launch Claude
- If synchronization fails, restart PC again (may require multiple reboots)

What Gets Preserved

✅ All conversations and projects
✅ Authentication state
✅ Memory and preferences
✅ Workspace files

Verified Migration Paths:

Windows 10 LTSC ↔ Windows 11 25H2

⚠️ Critical Notes

Before Running Any Operations

Always close Claude Desktop completely
- Check system tray
- Verify in Task Manager that Claude.exe is not running

Backup Guidelines

Backup both folders at the exact same time
Never restore only one folder - they must be synchronized pairs
Restoring mismatched versions will cause session errors

System Requirements

Windows 10/11 Pro/Enterprise/Education
- Windows Home is NOT supported (lacks full Hyper-V)

Virtual Machine Platform must be enabled:

Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform

Administrator privileges required for all operations

Troubleshooting

Cowork doesn't work after migration:

Restart PC (may need 2-3 reboots for junction sync)
Verify both folders were restored
Check AppContainer permissions with icacls C:\ClaudeData

"Plan9 mount failed" error:

You're on Windows Home (unsupported)
Upgrade to Pro/Enterprise/Education

🔍 Why These Two Folders?

Through extensive cross-PC testing, we confirmed that only these two folders contain all Cowork data:

vm_bundles/
- Contains VHDX virtual disk files
- Stores all workspace files and execution environment
local-agent-mode-sessions/
- Registry mapping sessions to VMs
- Preserves conversation history

They must be treated as a synchronized pair - backing up or restoring only one will break the system.

📝 Files in This Repository

File	Purpose
`move_claude_vmbundles.bat`	Launcher (run this)
`move_claude_vmbundles.ps1`	Main externalization script
`README.md`	This guide

🔗 Additional Resources

Detailed Technical Article (Japanese) - In-depth verification process and findings
Issues and pull requests welcome!

📄 License

MIT License

Author: Hiroto Kozuki
Verified Environments: Windows 10 LTSC, Windows 11 25H2
Last Updated: April 2026

Name		Name	Last commit message	Last commit date
LICENSE		LICENSE
README.md		README.md
move_claude_vmbundles.bat		move_claude_vmbundles.bat
move_claude_vmbundles.ps1		move_claude_vmbundles.ps1

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Claude Cowork Data Management Tool

🚨 Problem

🚨 Problem

✨ Primary Solution: Move VHDX to Another Drive

Step-by-Step Instructions

What Gets Moved

🔄 PC Migration (Cross-PC Restore)

Migration Procedure

On Old PC:

On New PC:

What Gets Preserved

⚠️ Critical Notes

Before Running Any Operations

Backup Guidelines

System Requirements

Troubleshooting

🔍 Why These Two Folders?

📝 Files in This Repository

🔗 Additional Resources

📄 License

Claude Cowork Data Management Tool

🚨 Problem

✨ Primary Solution: Move VHDX to Another Drive

Step-by-Step Instructions

What Gets Moved

🔄 PC Migration (Cross-PC Restore)

Migration Procedure

On Old PC:

On New PC:

What Gets Preserved

⚠️ Critical Notes

Before Running Any Operations

Backup Guidelines

System Requirements

Troubleshooting

🔍 Why These Two Folders?

📝 Files in This Repository

🔗 Additional Resources

📄 License

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