4. Run a full scan of your computer
Run a full scan of your computer using the antivirus solution installed on your device, and check if it helps.
Any infected data files may be cleaned only by completely deleting the file in its entirety, meaning there is a possibility of losing data.
Use a reliable, powerful tool to remove malware for good. Also, allow it to run in real-time, to prevent possible attacks
5. Restart in Safe Mode
- Click on Start button.
- Select Settings (the Settings box will open up).
- Click Update & Security.
- Select Recovery from the left pane.
- Go to Advanced startup.
- Click Restart now
- Select Troubleshoot from, then choose an option screen.
- Then click Advanced options.
- Go to Startup Settings and click Restart.
- Once your computer restarts, a list of options will come up.
- Choose 4 or F4 to start your computer in Safe Mode.
Note that there are two options:
- Safe mode (regular)
- Safe mode with Networking
The two are similar, though the latter includes network drivers and other services necessary to access the web and other computers in the same network.
The cng.sys file is critical to the functionality of Windows, so any corruption or damage on this file can create serious system errors, Blue Screens of Death included.
Safe Mode starts up your computer with limited files and drivers but Windows will still run. To know whether you’re on Safe mode, you’ll see the words at the corners of your screen.
If the cng.sys issue persists, check whether it occurs while your computer is in Safe mode.
If the cng.sys problem isn’t there while in Safe mode, then your default settings and basic drivers are not contributing to the issue.
Once you start your computer in safe mode, do the following:
- Right-click on Start.
- Select Device Manager.
- Expand Display adapters.
- Right-click the listed adapter.
- Select Uninstall device.
- Choose the Delete the driver software for this device box.
- Select Uninstall.
- Reboot your computer.
Once your computer reboots, click Start, choose Settings, then select Update & Security > Windows Update > Check for updates.
How to exit Safe Mode:
- Right-click the Start button.
- Select Run.
- Type msconfig.
- A pop up will open.
- Go to the Boot tab.
- Deselect or uncheck Safe Boot option box.
- Restart your computer.
6. Run disk clean up
- In the search bar on the home screen, type disk cleanup.
- The disk cleanup drive selection box will appear.
- Click OK to set off the disk space calculation process.
- Go to Properties > Tools > Error checking.
- Check the box and click Run.
Before doing this, ensure you have sufficient disk space on Windows drive.
7. Perform a Startup Repair
- Tap on the F8 key on your computer.
- Do this until you reach the Advanced Startup Options menu.
- Choose Repair your computer.
- Click Startup Repair.
If these steps didn’t fix the issue, try the steps below:
- Restart your computer.
- Boot to the Advanced Startup Options menu.
- Select Disable automatic restart on system failure.
Blue screen errors associated with cng.sys file can occur if a serious problem causes Windows to shut down, or reboot unexpectedly. Such errors occur due to hardware and software problems.
If you added new hardware before you got the cng.sys error, shut down the computer, remove the hardware, and then reboot (you can also boot in Safe Mode).
8. Perform an SFC scan to fix cng.sys missing error
- Press Windows + X keys at the same time
- Click Command Prompt (Admin) to open a command prompt
- If prompted for permissions, click Yes
- In Command prompt, type sfc/scannow and press Enter.
Wait for the process to finish. it should take about 15-20 minutes and hopefully it will also restore your device’s functionality.
9. Update drivers
This is more of a last resort if all else fails. Visit the manufacturer’s website and install the latest drivers available for your version of Windows (or latest).
Or, you can use a third-party driver updater like DriverFix. It will detect outdated or missing drivers in no time, with a single click.
These were our solutions to fix cng.sys file missing on a Windows PC. We’d like to hear if any of them helped and which one. Use the comments section.
Editor’s Note: This article was originally published in October 2017 and was revamped and updated in February 2021 for freshness, accuracy, and comprehensiveness.
This post was written by Milan Stanojevic and was first posted to WindowsReport