Why am I unable to update or edit my Master Plan?
When first opened, a Master Plan and its related Sub plans are Read-Only. This allows many users to open, read, run, and generate reports on the plan. When you need to actually edit the Master Plan or a Sub plan, you must first acquire a lock, which prevents others from making changes that conflict with your changes.
If you look at your Master Plan and see a grey bar running down the left-hand side of the plan, then you will know that the plan is currently in a Read-Only mode. To acquire a lock, go to Include\Acquire Lock. You will notice that the grey bar will now be yellow and you are in Edit mode.