How to fix ctfmon.exe sihost.exe explorer.exe System Warning Unknown Hard Error on Windows?

Problem

explorer.exe System Warning dialog box show with “Unknown Hard Error” message when playing a game on Windows 7, 8 or 10 laptop or desktop Windows. Other related error message may be Blue Screen of Death (BSoD) of Unknown Hard Error, sihost.exe Unknown Hard Error and the ctfmon.exe Unknown Hard Error, etc.

Possible cause

• Corrupted or incorrectly configured system files
• Corrupted Windows Registry due to a recent software change
• Hard disk problems
• Faulty device drivers
• Virus or malware

Solution 1: SFC.exe (System File Checker) Scan

Execute SFC command to scan for corruptions in Windows system files and restore corrupted files.

1. Open CMD (command prompt) with Run As Administrator option.
2. Type following command: sfc /scannow, then press Enter. The result will be shown after SFC scan completed.

Solution 2: CHKDSK (check disk) command

Execute chkdsk command to verifies the file system integrity of a volume and fixes logical file system errors.

1. Open CMD (command prompt) with Run As Administrator option.
2. Type following command: chkdsk /f /r, then press Enter.

Solution 3: Clean boot Windows 10

1. Login Windows 10 as Administrator.
2. Open CMD (command prompt) with Run As Administrator option.
3. Type following command: msconfig, then press Enter.
4. On the System Configuration windows, go to General tab, choose Selective Startup option then uncheck Load startup items.
5. Go to Services tab, check Hide all Microsoft services then click Disable all button.
6. Go to Startup tab, click on each startup item and select Disable all.
7. Click OK on the System Configuration window.
8. Reboot computer.
9. If this fixed the Unknown Hard Error, you should enable the services one by one to find out which one is the culprit. Several people reported the Realtek Audio Service causes all of the problems.

Solution 4: Repair System Partition

1. Open Windows Explorer.
2. Right-click on the drive or partition where your operating system is currently installed (Local Disk C by default) then click Properties option.
3. Switch to Tools tab and click on Check under Error checking section.
4. Restart computer.

Solution 5: Use Different Account to login computer

1. Logout from current user account.
2. Login via another user account by either restarting computer or by clicking the Start menu > Account icon > Sign out.

Solution 6: Roll back Windows update

For Windows 10

1. Click Windows key + I to open Settings.
2. Select Update & Security and open Update History.
3. Select Uninstall Updates.
4. The system will open the list of updates in Control Panel applet. Select the update that you want to remove and select Uninstall.

For Windows 7

1. Login Windows as Administrator.
2. Go to Control Panel > Programs and Features > View installed updates.
3. Select the update that you want to remove and select Uninstall.

Solution 7: Update Windows to the Latest Version

1. Open CMD (command prompt) with Run As Administrator option.
2. Enter following command: wuauclt.exe /updatenow, press Enter.

Solution 8: System Restore

1. Start your computer to Safe Mode.
2. Open CMD (command prompt) with Run As Administrator option.
3. Enter following command: %systemroot%\system32\restore\rstrui.exe and Enter at the command prompt to start the System Restore feature.

Solution 9: Rename Event Log related files (only for Windows XP)

1. Open CMD (command prompt) with Run As Administrator option.
2. Enter following command: services.msc and Enter.
3. Double-click Windows Event Log services, stop the service and set the Startup type to Disabled.
4. Restart computer.
5. Go to c:\windows\System32\config and look for “Sysevent.evt, Appevent.evt, Secevent.evt” either rename or delete, they will be recreated.
6. Start the Windows Event Log service again, set the Startup type to Automatic.
7. Restart computer.