How to Increase Maximum Heap Size in Windows 7

The desktop heap size limits the number of open windows.

Windows 7 sets a limit to the amount of memory desktop windows can use. If you have a large amount of application windows open, you might see an “Out of Memory” error message or a blank window when you open another application window. You can allot more memory to desktop applications by increasing the maximum heap size in the Windows registry.

Instructions

1. Click “Start,” type “Regedit” into the search box and press “Enter.”

2. Click “Yes” in the User Account Control window that appears.

3. Navigate to the “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\SubSystems” entry in the left pane of the Registry Editor.

4. Double-click the “Windows” value in the right pane.

5. Locate the “SharedSection=” text in the Value Data box.

6. Increase the value of the second and third numbers after "SharedSection." For example, change “SharedSection=1024,3072,512” to “SharedSection=1024,20480,1024.”

7. Click the “OK” button to save your changes.

8. Close the Registry Editor and restart your computer.

Tips & Warnings

• Ensure you don’t accidentally modify any other portion of the text in the Value Data box. The Windows value contains a long line of text with a variety of Windows settings.

• Microsoft recommends not setting the second number to a value above 20480.

References

• Microsoft Support: You May Receive an "Out of Memory" Error Message Because of the Dssktop Heap Limitation in Windows Vista or in Windows 7