How to Use the slmgr /rearm Command to Reset Windows Activation (2026 Step-by-Step Guide)
Quick Answer: How to Use the slmgr /rearm Command
To reset your Windows activation evaluation timer or clear corrupted licensing tokens, open Command Prompt as Administrator, type slmgr /rearm (or slmgr.vbs /rearm), press Enter, and restart your PC. This resets the evaluation grace period by 30 days and can be executed up to 3 times (for a maximum of 120 days). Check your remaining rearms at any time by running slmgr /dlv.
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If you have been battling stubborn Windows activation errors or testing evaluation builds, you might have stumbled across technical forums recommending the slmgr /rearm command. But what exactly does this command-line tool do, and how does it affect your operating system?
In this guide, we break down how the Software Licensing Management Tool works, when to use the rearm switch, and provide a safe walkthrough to clear corrupted licensing caches.
1. What Does slmgr /rearm Actually Do?
The slmgr rearm Windows activation command is a built-in Windows administrative tool that resets the licensing status of your machine back to its original state. Running this command performs two critical operations:
- Resets the Evaluation Timer: If you are running an unactivated evaluation copy of Windows (such as a fresh install without a product key), it resets the 30-day grace period, temporarily suppressing the “Activate Windows” watermark.
- Clears Corrupted Activation Tokens: If your PC has conflicting product keys installed, or a corrupted registry file is blocking a genuine activation, “rearming” clears the token cache so you can input your key on a fresh foundation.
Note: Microsoft limits the rearm command to 3 to 4 times depending on your exact Windows edition.
2. Step 1: Open Command Prompt as Administrator
- Click on the Windows Start button.
- Type cmd into the search bar.
- Right-click on Command Prompt and choose Run as administrator.
- Click Yes on the User Account Control (UAC) prompt.
3. Step 2: Execute the Rearm Command
Press Enter. A Windows Script Host dialog box will confirm: “Command completed successfully. Please restart the system for the changes to take effect.”
4. Step 3: Restart Your PC and Verify
- Close Command Prompt and restart your computer.
- Once rebooted, press Windows Key + I to open Settings.
- Navigate to System > Activation to confirm the system state is clean and ready for permanent activation.
5. SLMGR Commands Quick Reference Table
| Command | Function / Purpose | Admin | Reboot |
|---|---|---|---|
| slmgr /rearm | Resets activation grace timer by 30 days & clears corrupted tokens | ✅ Yes | ✅ Yes |
| slmgr /dlv | Displays detailed license information and remaining rearm count | No | No |
| slmgr /xpr | Shows current license expiration date or confirms permanent activation | No | No |
| slmgr /ipk <key> | Installs a new 25-character genuine Windows product key | ✅ Yes | No |
| slmgr /ato | Forces immediate online activation through official Microsoft servers | ✅ Yes | No |
Stop Resetting 30-Day Trial Timers — Activate Windows Permanently
Running slmgr /rearm is only a temporary fix. Permanently remove the activation watermark, unlock BitLocker encryption, and bind a genuine retail key to your Microsoft account.
7. Frequently Asked Questions
How many times can I use slmgr /rearm?
In most standard Windows 11 and Windows 10 retail installations, the rearm command can be executed up to 3 times. Each rearm extends the grace timer by 30 days, giving you a total of 120 days. You can view your exact remaining count by running slmgr /dlv in Command Prompt.
Why do I get error 0xC004D307 when running slmgr /rearm?
Error 0xC004D307 indicates that the maximum allowed number of rearms has been reached for your current Windows installation. At this point, running the command again will fail, and you must activate Windows with a genuine retail product key or reinstall the operating system.
Can slmgr /rearm permanently activate Windows?
No. The rearm parameter is explicitly designed by Microsoft as a temporary evaluation reset mechanism for administrators and developers. It resets the evaluation clock, but will never permanently license the operating system without entering a legitimate 25-character digital product key.
I ran `slmgr /rearm` in Command Prompt but received error code 0xC004D307 stating the maximum allowed number of re-arms has been exceeded. Is there any way to reset the counter in the registry, or is a permanent key required at this stage?
Hi David! Error 0xC004D307 triggers once Windows hits its absolute hard limit of re-arms (typically 3 times for a total of 120 days). While older registry tweaks existed for earlier Windows builds, recent Windows 10 and 11 cumulative security updates patch those workarounds. Once the counter reaches zero, rearming is exhausted and your system will require a genuine retail license. You can activate permanently with an authentic Windows 11 Professional Retail Key from our store to eliminate the watermark and unlock full personalization with zero data loss.
My system was successfully rearmed yesterday, but after this morning’s Windows Defender update, my desktop background went black and the activation watermark came back. Why does it keep reverting?
Hello Elena! The Windows Software Protection Service (
sppsvc.exe) runs periodic hardware validation sweeps during Windows Defender updates. If your hardware hash detects an unverified licensing state, Windows revokes personalization features even before the 30-day grace timer finishes. To permanently lock in personalization (custom themes, dark mode, taskbar customization) and stop the watermark permanently, binding a verified retail key to your Microsoft account is the only lasting solution.