The System File Checker (sfc.exe) is a useful tool that lets you scan the integrity of Windows system files, and repair corrupt or missing system files. Numerous cases have been resolved thus far by running the
sfc.exe /scannow command.
However, there are situations wherein a corrupt or missing system file prevents Windows from booting normally, or prevents Command Prompt and console programs like Sfc.exe from being launched. In such cases, Sfc.exe can be run offline via the Windows Recovery Environment (Windows RE) in all versions of Windows including Windows 10.
Run the System File Checker (Sfc.exe) Offline in Windows
Step 1: Booting into Windows Recovery Environment
Instructions for Windows 8 and 10
- Right-click Start, click Shut down or sign out, press and hold the Shift key and click Restart. In Windows 10, you can also open Settings (WinKey + i), click Update and Security, click Recovery, and click the Restart Now button under Advanced startup.
If Windows doesn’t start, then boot the system using the installation media or Recovery drive to access the Recovery Environment. In the Windows setup page that appears when booting using the Windows installation media, click Next and click Repair your computer.
- Click Troubleshoot
- Click Advanced options
- Click Command Prompt
- Use the BCDEDIT command to find the drive letter for your Windows installation, as seen from Windows RE.
More information here.
If Windows is installed in the
C:\drive, then it’s usually
D:\when seen from Windows RE. But it’s better to check it out using BCDEDIT.
(Now, proceed to Step 2 of the tutorial…)
Instructions for Windows Vista and 7
- Configure the boot order in the BIOS such that the first boot device is your CD/DVD drive.
- Insert the Windows 7/Vista Setup DVD and restart the computer.
Alternately, you may use the Windows 7/Vista System Repair Disc if you have one.
- When prompted, press a key to boot from the DVD.
- In the “Install Windows” screen, click Repair your computer
- Select your Windows installation, and click Next.
Make a note of the drive letter of your Windows 7 installation, as seen from Windows RE. This is the drive letter you want to reference when running Sfc.exe offline.
- Click Command Prompt
Step 2: Running the System File Checker Offline
To scan the integrity and repair a specific file, use this command:
sfc /scanfile=d:\windows\system32\zipfldr.dll /offbootdir=d:\ /offwindir=d:\windows
The above command scans the file zipfldr.dll and replaces it if required.
To scan the integrity of all system files and repair them, run this command:
sfc /scannow /offbootdir=d:\ /offwindir=d:\windows
In this example, there weren’t any integrity violations. If there were any it would be displayed, and logged in CBS.log file. For some reason, in Windows 10, integrity violations weren’t logged when SFC was run in offline mode.
About the author
Ramesh Srinivasan founded Winhelponline.com back in 2005. He is passionate about Microsoft technologies and he has been a Microsoft Most Valuable Professional (MVP) for 10 consecutive years from 2003 to 2012.