Fix ERR_MISSING_PARTNUMBER Office Activation Error

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ERR_MISSING_PARTNUMBER is a typing error that appears very often on your screen. It also occurs when you try to use the product key for an older version of Office that is no longer available for download. Errors can either be that the Office cannot create your account for the specific product, or that the product key could not be found in the Office database.

If the error message ERR_MISSING_PARTNUMBER is “Invalid product keys”, we can assume that you entered the product keys incorrectly or that you had to enter the product key on the incorrect product. This error code indicates that your computer may have registration problems. If you receive the error message “Invalid Product Key”, you can try the online Manual Solution Wizard step-by-step. Some of the errors are listed below.

If you have Microsoft Office 2010 installed on your system, Microsoft Office may reject previously valid keys at the time of reinstallation. When you try to reinstall Office with the 25-character product key, you may receive a message that your Office account cannot be configured at this time and you may be prompted to try the procedure later. If your product keys are verified, you can download or save the installation file from Microsoft’s backup site and then perform an installation to resolve the ERR_MISSING_PARTNUMBER error in Office 2013.

You may see one of the following error messages:

  • “We’re sorry, we are unable to create your account at this time. Please keep your product key and try again later. If this happens again, please contact support”. Error Code: ERR_MISSING_PARTNUMBER]
  • “Sorry, we can’t find this product key in our database. [Error code: ERR_INVALID_TOKEN]

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These messages appear when you enter a product key for an older version of Office that is not available for download at You can enter these product keys here.

For Office 2010, check the length of your product key and follow these steps:

  • If your product key is 25 characters long and uses the XXXXX-XXXXX-XXXXX-XXXXX-XXXXX format, go to
  • If your product key is 27 characters long and uses the format XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XX, go to

For more information about Office 2011 for Mac, go to

For Microsoft 365 for Enterprise, go to Enter your product key for Microsoft 365 for Enterprise.

Re-activating a One-Time Purchase License

If you have already used a single purchase license for Office that allows installation on only one computer at a time, and you have not uninstalled the suite before resetting the computer or selling the computer, Microsoft’s activation server may trigger the ERR_MISSING_PARTNUMBER error because it thinks that you are actually trying to install the Office suite more than once.

If this scenario is true, you should contact a Microsoft Live agent and ask them to activate your license key.

Remember that when you contact a Microsoft Agent, you will be asked to provide certain security settings to confirm that you are the owner of the license key you are trying to activate. If everything is correct, your Office license is activated remotely.

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