You're about to open a project that uses a resource pool file
The project you're about to open shares resources from a resource pool. A resource pool contains resource information (such as work schedules and pay rates) that other project files can share.
Using the Planning Wizard, you can:
Open the resource pool to see assignments across all sharer files.
Microsoft Project will open the resource pool file as well as all sharer files so that you can see all the resources and assignments that are shared across all the projects.
Not open other files.
Project will open only this file and no others.