Error Code 0XC004B100: How to Fix This Activation Error

Find out how our experts got things running

3 min. read

Updated onOctober 4, 2023

updated onOctober 4, 2023

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Key notes

Activating Windows is critical to an optimal experience, but the error code0XC004B100often stands in the way.

How do I fix the error code 0XC004B100?

1. Make sure you are entering the correct key

As perMicrosoft, the error code0XC004B100results from an incorrect MAK (Multiple Activation Key), so you must verify that first. Often, we enter a faulty activation key in a hurry, so take your time and check it once before submitting.

Also, if this is the first time you got the error, try again in a few hours since it could be a server-related problem. In case that doesn’t work, head to the next solution.

2. Run a diagnostic tool

Whenever you encounter the error code0XC004B100, the most viable solution is running an official tool from Microsoft, theSupport and Recovery Assitanttool, or theActivation troubleshooter.

This should get things running for most users, and even if the tool cannot eliminate the error, it will list the possible solutions.

3. Check for any hardware changes

A few users reported the error code0XC004B100after changing the hardware, usually the motherboard and CPU. Here, re-activating Windows becomes imperative and is often tricky.

In this case, you may be able toactivate Windows using the previous keyor have to get a new one, depending on how Windows was installed initially. In addition, windows licenses bought from a store or the Microsoft website are transferable, while those from the OEM are not.

If yours is,transfer the Windows licenseand get the device up and running. In case this, too, doesn’t work, head to the last solution.

4. Contact Microsoft Support

This is another way to fix error code0XC004B100when the servers seem to be giving you a hard time. Also, find out what to do when theWindows activate key is not working. Drop a comment below for queries or to share solutions that are not listed here.

Error Code 0XC004B100: How to Fix This Activation Error#

How do I fix the error code 0XC004B100?#

1. Make sure you are entering the correct key#

2. Run a diagnostic tool#

3. Check for any hardware changes#

4. Contact Microsoft Support#