How to Turn On or Off Compact OS in Windows 11

Does your computer feel cramped? Windows has a helpful feature called Compact OS that can save you storage space. In this guide, we’ll show you how to check if it’s on, turn it on, or turn it off.

What is Compact OS?

Compact OS squeezes your Windows system files smaller. Think of it like vacuum-sealing your clothes to free up closet space. When you turn it on, Windows keeps your files compressed and continues to save space as it updates them over time.

Learn more about Compact OS from Microsoft

Important Things to Know

• Admin privileges required — You must be logged in as an administrator to make these changes.
• This process takes time — Windows needs a few minutes to compress or uncompress your files, so be patient.

Step 1: Check if Compact OS is On or Off

Why do this? You need to know the current state before making changes.

What happens: You’ll see a message telling you if Compact OS is turned on or off.

1. Click the Start button.
2. Type Windows Terminal.
3. Right-click it and choose Run as administrator. ⚠️ Admin privileges required
4. In the window that opens, copy and paste this command, then press Enter:
   
   compact /compactos:query
5. Read the message:
   • If it says “Compact OS is enabled.” — it’s turned on.
   • If it says “Compact OS is disabled.” — it’s turned off.
6. Close Windows Terminal when done.

Step 2: How to Turn On Compact OS

Why do this? Turning on Compact OS saves valuable disk space.

What happens: Windows will compress your system files, which takes some time.

1. Open Windows Terminal as an administrator (follow Step 1 above). ⚠️ Admin privileges required
2. Copy and paste this command, then press Enter:
   
   compact /compactos:always
3. Wait while Windows compresses your files. This may take several minutes.
4. Close the window when finished.

Step 3: How to Turn Off Compact OS

Why do this? You might want to turn it off if you need faster file access or if you’re experiencing issues.

What happens: Windows will uncompress your files back to their normal size, which also takes time.

1. Open Windows Terminal as an administrator. ⚠️ Admin privileges required
2. Copy and paste this command, then press Enter:
   
   compact /compactos:never
3. Wait while Windows uncompresses the files. This can take several minutes.
4. Close the window when done.

Summary

• You must have administrator access to use Compact OS.
• Compact OS saves disk space by squeezing Windows system files smaller.
• Use these simple commands in Windows Terminal:
  • Check status: compact /compactos:query
  • Turn on: compact /compactos:always
  • Turn off: compact /compactos:never
• Be patient — compressing or uncompressing files takes time.
• Always check the status after running a command to make sure it worked.

Need more help? Check out Learn more about Compact OS from Microsoft for a video walkthrough and additional support.