The resolution is changed when you open the lid of a Windows Vista-based portable computer to resume from sleep mode

Consider the following scenario:

• You are running Windows Vista on a portable computer.
• The screen resolution is set to a resolution that is greater than 1024 × 768.
• You close the lid of the computer, and then it enters sleep mode.

In this scenario, when you open the lid of the computer to resume from sleep mode, the resolution changes to 1024 × 768.

This problem does not occur on desktop computers. Also, this does not occur on a portable computer when you use the Start menu to put the computer into sleep mode.

This problem occurs when the monitor driver is unloaded when the lid of the computer closes, and then the monitor driver is delayed from being reloaded when the computer resumes. In this case, the Transient Multi-monitor Manager (TMM) reduces the resolution to the default resolution of 1024 × 768 because it cannot verify the monitor.

To work around this problem, stop the TMM (Transient Multi-monitor Manager) service. To do this, use one of the following methods.

Method 1: Use Task Scheduler

1. Click Start
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   , type Task Scheduler in the Start Search box, and then click Task Scheduler in the Programs list.
2. Expand Task Scheduler Library, expand Microsoft, expand Windows, and then click MobilePC.
3. Right-click TMM, and then click Disable.
   
   Notes
   • If the TMM task is not displayed, right-click MobilePC, point to View, and then click Show Hidden Tasks.
   • This fix does not disable any of the docking features on the portable computer. The docking features of the portable computer are disabled only when you use an external monitor or a projector, and the portable computer is not docked. If you find that an external monitor does not work correctly, you can re-enable the TMM task or you can press F5 function key to enable the external monitor.

Method 2: Use a script

1. Click Start
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   , type cmd in the Start Search box, and then click cmd in the Programs list.
   
   
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   If you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
2. At the command prompt, type the following command, and then press ENTER:
   Schtasks /End /TN “\Microsoft\Windows\MobilePC\TMM”

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