Running SFC and DISM to Fix System Corruption

What Are SFC and DISM?

When Windows starts acting strange—crashes, error messages, features not working—the cause is often corrupted system files. Windows includes two powerful repair tools that most people don't know about: SFC (System File Checker) and DISM (Deployment Image Servicing and Management).

These are command-line tools, but don't let that scare you. We'll walk through exactly what to type.

Quick Fix: Running SFC First

SFC should be your first stop when you suspect corruption. Here's how to run it:

1. Click Start, type cmd
2. Right-click Command Prompt and choose Run as administrator
3. Click Yes when asked for permission
4. Type: sfc /scannow
5. Press Enter
6. Wait for the scan to complete (10-30 minutes)

Don't close the window until it says "Verification 100% complete." If SFC finds and fixes problems, restart your PC and see if your issue is resolved.

Understanding What Each Tool Does

SFC (System File Checker)

SFC scans all protected Windows system files and replaces corrupted ones with a cached copy stored in a compressed folder at %WinDir%\System32\dllcache. Think of it as Windows checking itself against a backup copy.

What it fixes: Corrupted DLL files, system executables, and core Windows components.

DISM (Deployment Image Servicing and Management)

DISM is more powerful. It repairs the Windows component store that SFC relies on. If SFC can't fix something, it's often because its source files are corrupted—that's when you need DISM.

What it fixes: The Windows image itself, component store corruption, and issues preventing SFC from working.

When to Use These Tools

Run SFC and DISM when you experience:

• Random crashes or freezes with no clear cause
• Error messages about missing DLL files
• Windows features not working (Store, Settings app, Start menu issues)
• Blue Screen errors related to system files
• After malware removal when Windows still acts strange
• Windows Update failures that keep repeating
• Apps crashing that worked before

The Correct Order: DISM First or SFC First?

There's debate about this, but here's the practical approach:

Start with SFC because it's faster and often sufficient. If SFC can't fix the problems, then run DISM to repair the component store, then run SFC again.

Think of it this way: SFC is the mechanic fixing your car, DISM is making sure the mechanic has working tools.

Running These Tools in Safe Mode

If your PC is too unstable to run these in normal Windows:

1. Restart your PC
2. Hold Shift while clicking Restart in the Start menu
3. Choose Troubleshoot > Advanced options > Command Prompt
4. Select your user account and enter password
5. Run DISM and SFC commands as described above

Interpreting the Logs

SFC and DISM create detailed logs. To view the SFC log:

1. Open Command Prompt as Administrator
2. Type: findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log > "%userprofile%\Desktop\sfcdetails.txt"
3. Press Enter
4. Open sfcdetails.txt on your Desktop

You'll see which files were corrupted and whether they were fixed. If many files are listed as "could not repair," you may need to reset Windows or use a System Image restore.

What If DISM and SFC Don't Fix the Problem?

If both tools complete but your problem persists:

1. Try System Restore

Restore to a point before the problem started (if System Restore is enabled).

2. Run Windows Update

Sometimes installing the latest updates replaces the corrupted files.

3. Reset Windows

Settings > System > Recovery > Reset this PC. Choose "Keep my files" to reinstall Windows without losing data.

4. Check Your Hard Drive

Disk corruption can cause these symptoms. Run: chkdsk C: /f /r (requires restart).

5. Consider Professional Help

If the corruption is severe or keeps returning, there may be failing hardware (RAM, hard drive) or deeper issues.

Common Errors and What They Mean

"Error 87 The parameter is incorrect"
You're not running Command Prompt as Administrator, or you mistyped the command.

"DISM does not support servicing Windows PE"
You're running from Windows Recovery instead of Safe Mode or normal Windows.

"Error: 0x800f081f The source files could not be found"
DISM can't download from Windows Update. Check your internet connection or firewall.

Preventing Future Corruption

• Don't force shutdown unless absolutely necessary
• Keep Windows updated to get corruption fixes
• Use a UPS to prevent power interruptions during updates
• Run disk checks occasionally: chkdsk C: /scan
• Monitor your hard drive health with CrystalDiskInfo
• Keep backups so corruption isn't catastrophic

Still Experiencing System Corruption?