It is possible to create a project from an Enterprise Project Type (EPT) or from Microsoft Project Professional that has no tasks, only the Project Summary task. In Project Online and some versions of on-premise Project Server 2016, if you have a project with only the Project Summary Task, the border around the name field is greyed out, making it appear that subtasks cannot be added in Project Web App (PWA), as shown in the following illustration:
While the Name field is read-only, the Mode, % Complete, and the Work columns (in the Task Summary view) are read-write and allow data to be entered. Once data is entered, then the name can be edited. Our recommendation is to select the Mode cell on the first blank line as shown in the following illustration:
Select the mode and hit the Enter key. A new task will be created as shown in the following illustration:
Now that one task has been created, the name can be edited, and additional tasks added as necessary.
This work around only applies to PWA: additional tasks can always be added in Microsoft Project Professional.
Applies To: Project Online, Project Server 2016 (some versions)