You are in single-project mode when you open only one project. When an EPS node containing one or more projects is open, or when you simply open two or more projects, you are in multiproject mode.
Most features function the same way in either single-project or multiproject mode. These include the Activity Table, Activity Network, and Gantt Chart; scheduling, applying actuals, and leveling resources; and thresholds, issues, tracking, and reporting features. The baselines, calendars, activity codes, work products and documents, and OBS features function slightly different in multiproject mode. For example, when saving a baseline in multiproject mode, the baseline saves to all projects in an EPS node, but not to the node itself. In multiproject mode, you can also assign a project's calendars, activity codes, and work products and documents to project elements. In addition, you can assign OBS elements to WBS elements, project thresholds, and project issues in the projects.
In multiproject mode, the work breakdown structures (WBS) and organizational breakdown structures (OBS) of the entire hierarchy are integrated. You can also define relationships between activities in different projects within the EPS hierarchy.
When connected to a P6 EPPM database: When you copy and paste a WBS within the same project, the WBS, activities, and associated risks from P6 are copied; risks are not copied when you copy and paste the WBS to a different project. Likewise, when you copy and paste activities within the same project, any associated risks are also copied; risks are not copied when you copy and paste activities to a different project.
When connected to a P6 Professional database: When you copy and paste a WBS within the same project, the WBS, activities, and associated risks are copied; risks are not copied when you copy and paste the WBS to a different project. Likewise, when you copy and paste activities within the same project, any associated risks are also copied; risks are not copied when you copy and paste activities to a different project.
Project security privileges function the same way in either single- or multiproject mode; a user can access any area of the WBS for which the user's assigned OBS is responsible.
To simplify potential confusion when in multiproject mode, all project-owned elements follow a simple rule: the project that owns the element is the only project that may use the element. For example, if Project A owns Document A, then Document A may only be assigned to activities within Project A, even if many other projects are also opened.