Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi Andy,
We will get this error message if we install an Office 365 product or a standalone Office 2013 or Office 2016 applications (Project, Access, Vision, Skype for Business or OneDrive for Business) when we have the 2013 or 2016 versions of Microsoft Office Professional Plus or Microsoft Office Standard already installed on computer.
We can't have Office products of the same version that use two different installation technologies installed on the same computer.
Please uninstall the Windows Installer version of Office with the steps in this article, then try to install Project again.
For detailed information, please refer to the article Office installed with Click-to-Run and Windows Installer on same computer isn't supported.
Regards,
Tina