Common Log (CLFS) Service Defaults in Windows 7

General-purpose logging service.

Default Settings

Startup type:Boot
Display name:Common Log (CLFS)
Service name:CLFS
Service type:kernel
Error control:critical
Group:Filter
Path:%SystemRoot%\System32\CLFS.sys
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CLFS

Default Behavior

Common Log (CLFS) is a kernel device driver. In Windows 7 it is being loaded by Boot Loader before Kernel initialization. If Common Log (CLFS) fails to load, Windows 7 attempts to write the error data into Event Log and restart the computer, using the Last Known Good configuration. If the Last Known Good configuration is not valid, Windows 7 startup ends with a Stop error. If you remove or disable the CLFS service, Windows 7 won't start.

Restore Default Startup Configuration for Common Log (CLFS)

1. Select your Windows 7 edition and service pack, and then click Download.

2. Save the Win7_CLFS_Service_Startup.cmd file to a local storage device.

3. Run the saved file as an administrator.

4. Restart the computer.

The CLFS service is using the CLFS.sys file that is located in the %WinDir%\System32 folder. If the file is changed, damaged or deleted, you can restore its original version from Windows 7 installation media.