Troubleshoot Error – 0xC004F042 KMS can’t be used.

If you encounter error code 0xC004F042 during Windows activation using KMS, the complete error message is as follows:

Error message

Error 0xC004F042: The Software Protection Service determined that the specified Key Management Service cannot be read.

This troubleshooting page will guide you step-by-step on resolving this KMS activation error.


If you come across this problem, it means that the KMS client attempted to connect with a KMS host that couldn’t activate the client software.

Solution 1: Fix common PC errors.

The initial step you should take is to address potential issues with an unoptimized and buggy computer, which could lead to the KMS activation error 0xC004F042. Download the Outbyte PC Repair Tool to scan and optimize your PC, resolving errors and improving response speed.

3 Steps to Fix this Error
Step 1. Download Outbyte PC Repair Tool [File Size: 16.4 MB]
Step 2. SCAN your Windows PC
Step 3. Click Fix button to Repair Error

Solution 2: Connect with the correct KMS host.

Mostly this error happens when a KMS client tries to connect with an incorrect KMS host, so to resolve the error code 0xC004F042 make sure to connect with the correct KMS host.

Solution 3: Update Windows, Drivers, and Apps

Ensure optimal performance and security by installing the latest feature updates, security updates, and cumulative updates for Windows 10/11. Additionally, keep your system up to date by installing or updating drivers and applications to their latest versions.

Complete Windows Updates - Step by Step

1. Windows Updates

Step 1: Right-click on Start → Settings.

open windows 11 settings

Step 2: Scroll down to find Windows updates and then click on Check for updates.


2. App Update

To update the installed application on your computer, you can follow the following steps.

Step 1: Open Microsoft Store. Click on your profile picture at the top of the MS Store and select Settings.

Open MS Store Settings

Step 2: Turn On App Updates.

Turn on Auto App Updates

Step 3: Open Microsoft Store Library. To access your Microsoft Store Library, simply click on the library icon located on the left sidebar. Once there, you’ll find a button labeled “Get updates.” Click on this to initiate a scan for the latest updates available for the apps you have installed.

Step 4: For the third-party application, check for their updated version on their official site and install them.

3. Driver Update

Step 1: Open Device Manager. Right-click on the Start menu and select Device Manager.

Open Device manager

Step 2: Expand all the drivers manually and look for the driver with a yellow exclamation mark. Right-click on it and select Update.


Solution 4: Try the Diagnostic tool.

Microsoft offers a Diagnostic tool to address activation-related issues, including error code 0xC004F042. Simply follow the instructions provided by the diagnostic tool to easily resolve activation-related issues.

Solution 5: Contact the Microsoft Support Team

If none of the above solutions prove effective, it is recommended to reach out to the Microsoft Support Team for further assistance. You can contact the Microsoft Support team via phone using the following details:

Step 1: Open the following link. It has a complete list of phone numbers.

Step 2: Find the phone number according to your country/region and call for support.


To troubleshoot the KMS activation error 0xC004F042, follow these steps:

  1. Ensure the KMS client matches the correct KMS host.
  2. Utilize the diagnostic tool provided by Microsoft.
  3. Update Windows with the latest features, security, and cumulative updates.
  4. If the issue persists, consider reaching out to the Microsoft Support Team for further assistance.