How to Fix the Cldflt.sys Blue Screen Error in Windows? (11 Ways)

Fix & Repair Solved issue

Question asked by:

Ron U.


I saw a blue screen stating "Cldflt.sys error" and my PC reloaded


I just saw an error saying something with "Cldflt.sys". Then it rebooted. Had this 5x different times.
How can I resolve this?

Thank you!
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Encountering the Cldflt.sys Blue Screen of Death Error on Windows 10/11 can be troubling, often leading to sudden system crashes and disruptions.
This comprehensive guide examines the common reasons behind this error, explores how it manifests, and provides a range of solutions — from quick fixes to more advanced troubleshooting methods.

How to Fix the Cldflt.sys Blue Screen Error

What Does This Error Look Like?

When the Cldflt.sys error occurs, users are often met with the infamous blue screen (a BSOD1 ) containing an error message. These messages can vary but typically highlight issues related to the Cldflt.sys file. Personal accounts from affected users might shed light on system crashes or unexpected reboots, adding context to the error.

Now let’s see some of the main reasons why it occurs and how can we fix it!

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TL;DR: Quick Fixes You Can Try Right Away

For users seeking immediate relief, a summary of quick fixes includes: 

  • Updating drivers — especially graphics and storage drivers.
  • Running Windows Update to install the latest patches.
  • Performing a comprehensive antivirus scan to eliminate potential malware causes.

Usual Reasons for Cldflt.sys BSOD Error

This error may arise from corrupted system files, incompatible drivers, or disruptions during Windows updates. Understanding these factors is essential for implementing effective solutions tailored to the root cause of the problem.

Upon thoroughly examining numerous user reports and references, it becomes evident that the cldflt.sys blue screen error can primarily be based on the following sources:

Third-Party Program Conflicts
The conflict between third-party programs installed on your system may lead to the Cldflt.sys BSOD error. Identifying and resolving any disputes arising from applications that might interfere with system processes is essential.

Incompatible Driver Versions
Outdated or incompatible drivers, particularly those related to hardware components such as graphics cards or storage devices, can trigger the Cldflt. sys error. Ensuring all drivers are up-to-date is crucial in preventing such compatibility issues.

Buggy Windows Updates
Occasionally, Windows updates may introduce bugs or compatibility issues with existing system components, including the cldflt.sys file. Keeping your system updated is essential, but observation is equally important to avoid potential dangers.

Corrupted System Files
Corruption within essential system files, including cldflt.sys, can lead to the blue screen error. Conducting system file integrity checks and repairs can address these issues and restore stability.

Virus or Malware Infection
The presence of malicious software on your system can significantly disrupt normal operations, potentially causing the Cldflt.sys BSOD error. Regular antivirus scans and a robust security regimen are essential for preventing and resolving such infections.

These issues might cause other BSOD errors as well. See what a BSOD is and how you can fix them here!

5 Easy-to-Follow Solutions to Fix Cldflt.sys Error (Time to Complete: ~7-12 mins)

Let’s begin by exploring the easiest ways first. Try implementing the steps in given order to effectively solve the Cldflt.sys error.

Solution #1: Run Windows Memory Diagnostic

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  • Access the Run dialog (Win + R), type “mdsched.exe”, and hit ‘Enter’.
Type mdsched
  • Choose to restart your system and check for memory-related problems.

Solution #2: Uninstall Third-Party Programs

Remove KeepassOneDriveSync
  • Remove programs like “Keepass” or “KeepassOneDriveSync” utility, as third-party conflicts could be at the root of the cldflt.sys error.

Solution #3: Install/Uninstall Windows Updates

Manually Installing Windows Updates using Microsoft Update Catalog
  • Update your system with recommended updates (e.g., KB4530684 or KB4522355) and uninstall any potentially buggy updates (e.g., KB4517389). Keeping your system up-to-date is crucial.

Solution #4: Update Device Drivers

  • Ensure all your device drivers are updated to their latest versions. Outdated or incompatible drivers can contribute to the blue screen error.

Solution #5: Run Windows Defender

  • Conduct a thorough scan using “Windows Defender” to eliminate potential malware or virus infections.
Virus & Threat Protection Scan options

6 Advanced Solutions to Fix Cldflt.sts BSOD (Time to Complete: ~10-20 mins)

If the easy ways to fix the error didn’t get it done, no worries, we still have some advanced ways to help you solve the issue. Let’s try them out!

Solution #6: Reinstall Corrupted Cldflt.sys With SFC Command

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  • Open an elevated “Command Prompt”.
Type CMD then run as administrator
  • Execute the command: sfc /scannow to initiate a scan and repair of system files.
Type sfc scannow

Solution #7: Verify Windows Update Services

  • Access “Services” (services.msc).
Type services.msc
  • Ensure both the “Windows Update” and “Background Intelligent Transfer” service are running.

Solution #8: Run SFC and DISM Tasks

Corrupted system files may be the culprit. Try the following steps:

  • Open “Command Prompt” as an administrator.
Type CMD then run as administrator
  • Execute sfc /scannow and restart your PC.
Type sfc scannow
  • If the issue persists, run DISM commands:
    DISM.exe /Online /Cleanup-image /CheckHealth

    DISM.exe /Online /Cleanup-image /ScanHealth
    DISM.exe /Online /Cleanup-image /RestoreHealth

Solution #9: Modify Registry Entry

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Adjusting the Registry entry might resolve the error:

  • Open the Run window with ‘Win + R’.
  • Type “regedit” and press ‘Enter’.
Type regedit
  • Navigate to Computer/HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/CldFlt/Instances.
  • Right-click on “DefaultInstance”, choose “Modify”, enter “CldFlt” in the Value data field, and click “OK”.
Modify Registry Entry CldFlt

Reboot your PC and check for resolution.

Solution #10: Perform a Clean Boot

Identify conflicting services with a “clean boot”. Refer to the post onHow to Clean Boot Windows 10 to troubleshoot and isolate problematic software.

Check Hide all Microsoft services

Solution #11: Do a Full System Restore

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Consider performing a “system restore” by choosing an earlier, stable system point and restoring Windows to that point.

System Restore

Encountering the cldflt.sys blue screen error can be disruptive don’t be alarmed. Here, we separate 6 practical solutions to address and resolve this issue.

Is It Successfully Fixed Now?

We certainly hope that a total of 11 solutions we provided you did the trick for you!

Fixing the Cldflt.sys Blue Screen Error on your computer needs a careful approach.
Be careful, especially when doing advanced troubleshooting, and it is a good idea to back up your important files before making big changes.

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If your Cldflt.sys errors are still not fixed — feel free to reach out to us via email and share your problem.

  1. What is a Blue Screen of Death? – via []
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About the author
Iggy Shells
Iggy Shells - IT & PC repair expert

Iggy is the founder of He’s been involved in custom IT and security solutions for more than a decade.

Now he and his team are sharing their knowledge with the world by helping casual users solve a myriad of different computer issues, system errors, and virus/malware infections.