You have to activate your Microsoft products to confirm that each copy of the product is not installed on more than the limited number of computers that is indicated in the software end user license agreement (EULA). The activation process can be performed by using the telephone, a modem, or the Internet. None of the information that is collected during activation will be used to personally identify you.
Update Office Application
You can update each office application individually. Let us try with MS Word application.
· Open MS Word and click on File tab
· Go to Account and Select Update Options
· Click on Update Now button
For more solutions Activate office 2016 with a product key
Note Registration of a Microsoft product does not provide to us your proof of purchase for that product. You should maintain any receipts or records of your purchases of Microsoft products in case you need to obtain replacement media or product keys. For more information about obtaining replacement media or product keys, click the following link Activate office 2016 with a product key.
After following above mentioned method, try to open email attachments, if it does not work, reinstall your MS Office suite. Before installation, completely uninstall it from your computer. Then, open downloaded documents.
If you fail to open Office documents even after Office suites reinstallation, then there is chance of document corruption. To fix the corrupted documents, you can make use of File Repair Tool. In case, you want to repair Word files, then use Remo Word Repair Tool. The software comes handy to activate office 2016 with a product key