Reduced Functionality mode After the grace period, if you have not entered a valid Product Key, the software goes into Reduced Functionality mode. In Reduced Functionality mode, your software behaves similarly to a viewer. You cannot save modifications to documents or create new documents, and functionality might be reduced. No existing files or documents are harmed in Reduced Functionality mode. After you enter your Product Key and activate your software, you will have full functionality for the programs and features that you purchased.