If you have created a master project that contains external links to other projects, task and resource information in the other projects is automatically updated in the master project. You can suppress these automatic updates in order to, for example, simplify projects by consolidating them.
On the View menu, click Gantt Chart.
Select the task that represents the linked project.
Click Task Information , and then click the Advanced tab.
In the Inserted Project Information dialog box, clear the Link to project check box.
When you unlink a subproject, the subproject and all of its tasks become tasks in the master project.
Tip: To link the projects again, you must delete the task created when you unlinked the subproject, and then reinsert the source file.
Note: Typically, if you create master projects and subprojects, only the subprojects are saved to the enterprise server. The master projects are only saved locally, unless your organization has specified that they can be saved to the server.