Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear P Mounts,
Greetings! Thank you for posting in Microsoft forum.
According to the support article, when viewer mode is enabled, an unlicensed user of Microsoft 365 Apps for enterprise isn't prompted to activate Office when they open Word, Excel, or PowerPoint. I understand your requirement is related to the license user, I checked but there’s no information available on this.
Article does say “If viewer mode is enabled, but the user has a license for the product, such as Visio, then the user will have an activated, fully functional version of that product. The other unlicensed products on the device, such as Project, will remain in viewer mode”, since Outlook is the part of Microsoft 365package, it can be either licensed or unlicensed/ViewerMode like other apps in the suite. Further, as the viewer mode is enabled via group policy, I will suggest you check the group policy settings to confirm if this is possible.
If you need any help with group policy, please post a new question is Microsoft Q & A forum for expert assistance. Since, we do not have enough experience in troubleshooting group policy, we are afraid we are not of much help further as our area of expertise is Microsoft 365 services (basic support such as installation and activation issue). We are sorry for not being able to help. While posting in Microsoft Q & A forum, please tag Windows-group-policy.
Thank you for your cooperation and understanding!
With sincerest regards,
Neha Singh | Microsoft Community Moderator