How to Fix the “CldFlt Service Failed to Start” Error on Windows 11 – A Comprehensive Expert Guide

The CldFlt (Cloud Filter) service is a core component of OneDrive’s Known Folder Move (KFM) and Files On-Demand features in Windows 11. When you encounter the error:

“CldFlt Service failed to start”

It typically prevents OneDrive synchronization, especially for users relying on cloud-based file access without local storage.

As a Windows system and cloud integration expert, I will guide you through:

• ✅ Root causes of the CldFlt service failure
• ⚠️ Step-by-step troubleshooting with technical insights
• 💡 Advanced tools: Registry Editor, Command Prompt, PowerShell, and DISM
• 🧩 Best practices for managing OneDrive, cloud services, and system integrity

Let’s begin.

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🔍 Overview

What is the CldFlt Service?

The CldFlt service stands for Cloud Filter Driver, part of the Microsoft Cloud Files Mini Filter Driver. It enables:

• OneDrive Files On-Demand: Sync files without downloading them locally
• Known Folder Move (KFM): Redirect Desktop, Documents, etc., to OneDrive
• Seamless cloud-to-local file experience

This driver runs as a system mini-filter driver, integrated with the NTFS file system.

Common Scenarios Where This Error Occurs

Scenario	Description
OneDrive fails to sync	Especially after OS upgrade or fresh install
KFM fails to redirect folders	Due to missing or corrupted CldFlt driver
System crash or BSOD	In rare cases, due to faulty filter drivers
After disabling or modifying system components	e.g., Storage Sense, Sync Providers

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🔧 Step-by-Step Troubleshooting Guide

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✅ Step 1: Verify CldFlt Driver Installation

Steps:

1. Open Device Manager (devmgmt.msc)
2. Expand Disk drives
3. Look for:

   Microsoft Cloud Files Mini Filter Driver

If missing:

• Reinstall the OneDrive client
• Or run system file repair (see Step 5)

⚠️ Note: Do not manually uninstall this driver—it is tightly integrated with Windows

💡 Tip: Use fltmc command to list loaded filter drivers:

fltmc filters | findstr /i cldflt

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✅ Step 2: Check OneDrive Settings and Status

Since CldFlt is tied to OneDrive, ensure it’s running properly.

Steps:

1. Open Task Manager > Startup tab
2. Ensure OneDrive is enabled at startup
3. If not running:

• Press Windows + R, type:
  cmd %localappdata%\Microsoft\OneDrive\onedrive.exe /background

1. Wait for OneDrive to initialize
2. Check if CldFlt starts automatically

⚠️ Note: If OneDrive crashes, check logs under:

%localappdata%\Microsoft\OneDrive\onedrive.log

💡 Tip: Reinstalling the latest version of OneDrive may resolve compatibility issues

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✅ Step 3: Enable Required Group Policy Settings

Certain policies must be enabled for CldFlt to function correctly—especially in domain environments.

Steps:

1. Run:

   gpedit.msc

2. Navigate to:

   Computer Configuration > Administrative Templates > System > Filesystem > Cloud Files

3. Ensure the following policies are set to Enabled:

• Enable Cloud Files support
• Allow Known Folder Move integration

3. Apply changes and restart the machine

⚠️ Note: These settings may be overridden by domain policies—contact your IT admin if applicable

💡 Tip: Use rsop.msc to verify applied policy settings

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✅ Step 4: Repair Corrupted Registry Entries

Misconfigured registry keys can prevent the CldFlt service from starting.

Steps:

1. Open Registry Editor (regedit) as Administrator
2. Navigate to:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CldFlt

3. Ensure the following values exist and are correct:

• Start = 3 (Manual)
• Type = 0x00000010 (File system driver)
• ImagePath = \SystemRoot\System32\drivers\CldFlt.sys

3. Also check:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation

Ensure:

• DependOnService includes CldFlt

⚠️ Warning: Always back up the registry before making any changes

💡 Tip: Use Process Monitor (ProcMon) to trace registry access failures during boot

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✅ Step 5: Run System File Checker and DISM

Corrupted system files can break the CldFlt driver and other critical components.

Steps:

1. Open Command Prompt as Administrator
2. Run:

   sfc /scannow

3. If SFC reports corruption but cannot fix it:

   DISM /Online /Cleanup-Image /ScanHealth
   DISM /Online /Cleanup-Image /RestoreHealth

For deeper cleanup:

DISM /Online /Cleanup-Image /StartComponentCleanup

⚠️ Note: Internet connection required for DISM to fetch healthy files

💡 Tip: Boot into WinRE and run DISM from there if online repair fails

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✅ Step 6: Reinstall or Update OneDrive Client

A broken or outdated OneDrive client can cause CldFlt to fail.

Steps:

1. Uninstall current OneDrive:

• Go to Settings > Apps > Installed apps
• Search for OneDrive, click Uninstall

1. Download latest OneDrive installer:

• https://onedrive.live.com/about/en-us/download/

1. Install using elevated permissions:

   msiexec /i OneDriveSetup.exe /quiet

4. Restart and log in again

⚠️ Note: Avoid third-party installers or outdated versions

💡 Tip: Use Group Policy or Intune to deploy OneDrive in enterprise environments

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✅ Step 7: Reset OneDrive Cache and State

Sometimes, cached data or sync state can interfere with CldFlt initialization.

Steps:

1. Stop OneDrive:

• Right-click tray icon > Exit
• Or use Task Manager

1. Delete cache:

   cd /d %localappdata%\Microsoft\OneDrive
   OneDrive.exe /reset

3. Clear local state:

   rd /s /q "%localappdata%\Microsoft\OneDrive\onedrive.exe"

4. Restart OneDrive:

   "%localappdata%\Microsoft\OneDrive\onedrive.exe"

⚠️ Warning: This will reset sync relationships—reconnect your account if needed

💡 Tip: Use /unlink to remove and re-link the account cleanly

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✅ Step 8: Re-enable CldFlt Through PowerShell

You can force-start the service or query its status using PowerShell.

Steps:

1. Open PowerShell as Administrator
2. Query service status:

   Get-Service -Name CldFlt

3. Start the service:

   Start-Service -Name CldFlt

4. Set to automatic startup:

   Set-Service -Name CldFlt -StartupType Manual

If service fails to start:

Get-WinEvent -LogName System | Where-Object { $_.ProviderName -eq "Service Control Manager" -and $_.Message -like "*CldFlt*" }

⚠️ Note: Some systems may require reboot after changing service state

💡 Tip: Combine with eventvwr.msc to analyze event logs in detail

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✅ Step 9: Update Storage and File System Drivers

Faulty or outdated storage drivers can conflict with CldFlt operations.

Steps:

1. Open Device Manager
2. Expand Storage controllers
3. Right-click each controller (e.g., NVMe, RAID, AHCI) > Update driver
4. Choose:

• Search automatically for updated driver software

If no updates found:

• Visit manufacturer’s website (Intel, AMD, NVIDIA, Dell, HP, etc.)
• Download latest chipset and storage drivers

⚠️ Note: Avoid generic PnP drivers—use manufacturer-specific ones

💡 Tip: Disable third-party disk encryption tools temporarily (BitLocker, VeraCrypt)

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✅ Step 10: Perform Clean Boot to Isolate Conflicts

Third-party services or drivers may interfere with CldFlt initialization.

Steps:

1. Press Windows + R, type:

   msconfig

2. Under Services, check Hide all Microsoft services
3. Click Disable all
4. Under Startup, open Task Manager and disable all startup items
5. Reboot

After clean boot:

• Try starting the CldFlt service again

⚠️ Note: Only use this method for diagnostic purposes

💡 Tip: Use Autoruns to selectively enable services/startup items

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📋 Summary Table: Methods to Fix CldFlt Service Failed to Start

Method	Pros	Cons
Verify CldFlt Driver	Quick check	Requires basic knowledge
Restart OneDrive Properly	Fixes minor sync issues	May need manual restart
Enable Group Policies	Fixes domain/KFM issues	Complex navigation
Registry Fix	Direct configuration	Risky without backup
System File Repair	Repairs core OS	Time-consuming
Reinstall OneDrive	Fixes client-side issues	Requires download
Reset OneDrive Cache	Clears corrupted state	May lose sync settings
PowerShell Commands	Automatable	Requires scripting knowledge
Driver Updates	Fixes hardware conflicts	Needs internet access
Clean Boot	Isolates conflicts	Major disruption

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🧪 Expert Use Case Scenarios

Scenario	Recommended Action
Corporate laptop with MDM	Contact IT department for GPO push
Home PC with personal OneDrive	Reinstall OneDrive and reset cache
Known Folder Move failing	Ensure GPOs are enabled
Cloud-only file access issues	Confirm CldFlt driver is active
Post-upgrade error	Run DISM/SFC scan

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📌 Final Expert Recommendations

✅ Do:

• Always keep OneDrive and system files updated
• Monitor event logs for early signs of service failure
• Maintain a recovery drive or ISO for WinRE access
• Regularly audit startup and service configurations

❌ Don’t:

• Manually delete or modify CldFlt driver files
• Force update services without diagnosing root cause
• Ignore warning messages in OneDrive logs or Event Viewer

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📚 Conclusion

The CldFlt Service failed to start error is often a symptom of deeper issues affecting OneDrive integration, file system health, or system policies. By methodically isolating the problem—from verifying OneDrive functionality to deep system repairs—you can restore seamless cloud file access.

By following this expert-approved guide, you now have the knowledge to:

• ✅ Identify and resolve the root cause behind the CldFlt failure
• ⚠️ Understand how to apply safe mode, registry edits, and system file repair
• 💡 Use advanced tools like PowerShell, ProcMon, and DISM for deep diagnostics

Remember:

• Start with simple checks like OneDrive status and service settings
• Only escalate to registry edits or system resets when necessary
• Treat this as a learning opportunity for future Windows cloud troubleshooting

With the right approach, you’re not just fixing a service issue—you’re reinforcing your skills in Windows system architecture and cloud integration, like a true Windows administration expert.