What Should You Do to Fix Windows Activation Error 0xC004E003?

Windows operating system is one of the most used operating systems on a computer worldwide. However, some people report that they encounter Windows activation error 0xC004E003 on their computer while they try to activate Windows 7/Windows 8/Windows 10/Windows 11. For instance, here is a user report from the answers.microsoft.com forum:

I format my last HDD with a win7 professional original. I tried to uninstall my slmgr command. then after in the new SSD I put Win 7 Pro and tried to activate but it is not taking. Giving error 0xC004E003…If anyone can guide me, please?https://answers.microsoft.com/en-us/windows/forum/all/windows-7-activation-error-0xc004e003-how-to/e4656b38-aec3-44cd-8d6a-bd34a3dad920

Have you also experienced the same error? No matter if you run into Windows 7 activation error 0xC004E003, Vista activation Error Code: 0xC004E003, Windows 11 activation error 0xC004E003, or Windows 10 activation error 0xC004E003, just keep reading, you can get the possible reasons for the activation error and some useful solutions.

Why Encounter the Windows Activation Error 0xC004E003?

After searching Windows activation error 0xC004E003 from various posts and reports, I find that the error can mainly be caused by these reasons:

• Invalid/signed incorrectly license
• Invalid/wrong product key
• Corrupt or damaged registry
• Corrupted/missing/tampered system files
• Accidently deleted Microsoft-related files

Fix 1. Retrieve the Lost Windows Files

The first way you can try to fix the Windows activation error 0xC004E003 is by recovering the lost Windows files. To do that, you can go to Recycle Bin, and find the lost file here. If not, you can try using MiniTool Partition Wizard to help you recover lost files.

Also, this multifunctional tool can help you partition hard drive, check disks for errors, format SD card FAT32, rebuild MBR, convert MBR to GPT, move/resize partitions, and more. To use it to recover lost Windows files, you can refer to this post: [SOLVED] How To Recover Permanently Deleted Files In Windows.

Fix 2. Perform a System Restore

You can also try performing a system restore to fix the Windows 7 activation error 0xC004E003, Windows 11 activation error 0xC004E003, or Windows 10 activation error 0xC004E003. It can revert your operating system to the state when all the system files or Microsoft-related files are not missing. Here’s how to do that on Windows 7 PC:

1. Press the Windows key, type “system restore” and press Enter.
2. Select Next, and then select the restore point you want to use from those in the list.
3. After that, click the Next button.
4. Next, click Finish. Then choose Yes to the “Once started, System Restore cannot be interrupted. Do you want to continue?” question.
5. Then the System Restore process will now begin. Wait for this process to be completed.
6. Once done, your Windows will revert to the previous state as you select. 

Fix 3. Active Windows via Phone

If the Windows activation error 0XC004E003 on your PC is unrelated to the missing Windows files, you can try active Windows via phone. Here’s how to do that:

1. Press the Win + R keys simultaneously to open the Run window.
2. Type “slui.exe 4” and press Enter.
3. Click OK and the Windows activation window will prompt.
4. Choose your country from the drop-down list and then select the phone activation option.
5. Then, you can see a window with a toll-free number.
6. Dial the number and follow the caller’s instructions to activate.

If you encounter the Windows 7 activation problem with 0xc004e003 error and are unable to do a phone activation, you can continue and try the following fixes.

Fix 4. Change the Product Key

If your key is invalid or incorrect, you can also run into the Windows 11 activation error 0xC004E003, Windows 10 activation error 0xC004E003, or Windows 7 activation error 0xC004E003. In this case, you can try a different product key to activate your Windows. To do that, you just need to do as follows:

1. Open the Run window.
2. Type “SLUI 3” in the box and press Enter.
3. Enter a valid product key and click Next to continue.
4. Then follow the on-screen instructions to complete the process.

Fix 5. Edit the Windows Registry

If none of the above solutions can help you fix the Windows activation error 0XC004E003, you can try repairing the Windows registry to fix the error. Here’s the guide for editing the Windows Registry on Windows 7:

Step 1. Press the Windows key, type “cmd” in the box and press Ctrl + Shift + Enter keys simultaneously to run Command Prompt as administrator.

Step 2. In the elevated Command Prompt window, type “regedit” and press the Enter key to open the Windows Registry window.

Step 3. Then, go to the following path:

HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/setup/OOBE/mediabootinstall

Step 4. Double-click MediaBootInstall, change its Value data to 0, and click OK to confirm. If the key doesn’t exist, create it and set its Value data to 0.

Step 5. Next, back to the Command Prompt window, type “slmgr /rearm” and press Enter.

Step 6. Restart your computer, and use the activate Windows link to re-enter the product key.

Fix 6. Try Some Other Ways

If you still unable to fix the Windows activation error 0XC004E003, you can do the following ways to fix the error and activate Windows successfully:

• Check the license type
• Run Windows activation troubleshooter
• Activate using Command Prompt
• Check internet connection
• Check time and date
• Reinstall Windows
• Contact Microsoft support

In Conclusion

This post provides the possible causes of the Windows activation error 0XC004E003 and several effective solutions to solve the error. If you also encounter the same error on your computer, you can try these methods individually until the error gets fixed.