Users may experience the Office error code 0x8004FC12 when upgrading to Windows 10 and Office is already installed on the machine. The Office suite becomes an “unlicensed product” and will then display the following error message below when activation is attempted.

 

 

Here are the steps to resolve the issue.

1. Open a command prompt as Administrator.

1. Start Type “CMD” in the search bar
2. Right click the Command Prompt
3. Click Run as Administrator

2. Run the following commands.

 

net localgroup Administrators localservice / add fsutil resource setautoreset true C:\

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3. Restart computer.

4. Activate Office again.