Is your Windows PC running slower than usual? Before installing third-party tools, you should try the powerful diagnostic and repair utilities already built into Windows. In this guide, we will show you how to use two of the most effective system commands:
- SFC (System File Checker)
- DISM (Deployment Image Servicing and Management)
These commands help fix corrupted system files, repair Windows images, and restore your computer’s performance — all without any external software.
🖥 Step 1: Open Command Prompt as Administrator
To run these commands properly, you must open Command Prompt with Administrator privileges.
How to do it:
- Click Start Menu
- Type cmd or Command Prompt
- Right-click Command Prompt
- Click Run as Administrator
You will see a black command window titled “Administrator: Command Prompt”.
🛠Step 2: Run System File Checker (SFC)
✔ Command:
sfc /scannow
✔ What This Command Does
- Scans all protected Windows system files
- Detects corrupted or missing files
- Automatically replaces them with cached, healthy versions
- Improves system stability and performance
Windows corruption often leads to slow performance, unexpected crashes, app errors, or startup issues. Running SFC ensures your core Windows files are clean and intact.
✔ What to Expect
- The scan may take 5–15 minutes
- You will see one of these results:
- No integrity violations found
- Found corrupted files and repaired them
- Found corrupted files but couldn’t repair (then you must run DISM)
🧹 Step 3: Run DISM to Repair the Windows Image
If SFC could not repair all files, or if you want deeper system repair, use the DISM command.
✔ Command:
DISM /online /cleanup-image /restorehealth
✔ What This Command Does
- Repairs the Windows system image stored on your PC
- Fixes component store corruption
- Prepares system files so SFC can repair them again if needed
- Solves problems like:
- Windows Update failures
- System crashes or freezes
- Missing system components
- Performance slowdown caused by OS corruption
✔ How Long It Takes
- Usually 10–25 minutes depending on system speed
- It may appear stuck at 20%, 40%, or 62% — this is normal
🔄 Recommended Order for Best Performance
To fully optimize Windows and repair corruption:
- Run DISM first
DISM /online /cleanup-image /restorehealth - Then run SFC
sfc /scannow
This ensures DISM repairs the underlying Windows image, and SFC fixes any remaining corrupted system files.
🚀 Final Thoughts
These built-in Windows commands are simple yet powerful tools that can:
- Fix slow performance
- Repair corrupted system files
- Solve update failures
- Restore overall system health
Running these once every few months helps keep your PC running at peak performance — all without any third-party software.
