When you open a master project in Microsoft Office Project, and then you expand the subprojects, Project may stop responding.

When you expand a subproject in a master project, Project loads the subproject data on demand. Additionally, Project caches some extra data in memory for the subproject. Project caches this data to improve performance. When the master project contains lots of subprojects, and the subprojects contain lots of data, the memory limit may be reached. When the memory limit is reached, Project stops responding.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this problem, follow these steps.

For Microsoft Office Project 2003

1. Install Project 2003 Service Pack 3 (SP3).
   
   For more information, click the following article number to view the article in the Microsoft Knowledge Base:
   923622  (http://kbalertz.com/Feedback.aspx?kbNumber=923622/ ) Description of Project 2003 Service Pack 3
2. Click Start, click Run, type regedit, and then click OK.
3. In Registry Editor, locate the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\MS Project
4. Right-click MS Project, point to New, and then click DWORD Value.
5. Type CloseSubProjHandleAfterOpen, and then press ENTER.
6. Double-click CloseSubProjHandleAfterOpen.
7. In the Edit DWORD Value dialog box, type 1 under Value data.
8. Close Registry Editor.

For Microsoft Office Project 2007

1. Install hotfix 958138 or hotfix 957880. For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
   958138  (http://kbalertz.com/Feedback.aspx?kbNumber=958138/ ) Description of the Project 2007 hotfix package (Project.msp): October 28, 2008
   957880  (http://kbalertz.com/Feedback.aspx?kbNumber=957880/ ) Description of the Project 2007 hotfix package: September 26, 2008
2. Click Start, click Run, type regedit, and then click OK.
3. In Registry Editor, locate the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\MS Project
4. Right-click MS Project, point to New, and then click DWORD Value.
5. Type CloseSubProjHandleAfterOpen, and then press ENTER.
6. Double-click CloseSubProjHandleAfterOpen.
7. In the Edit DWORD Value dialog box, type 1 under Value data.
8. Exit Registry Editor.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

After you install Project 2003 Service Pack 3 (SP3) or use Project 2007, and then you set the value of the CloseSubProjHandleAfterOpen registry entry to 1, Project loads the complete subproject when you expand a subproject. Project also releases the cached data. Therefore, Project consumes less memory. However, when you expand a subproject, the expand operation may take longer to finish. This is because Project loads the complete project instead of loading subproject data on demand.