I’ve been encountering problems in Vista on my multi-monitor equipped desktop computer where the resolution would get reset to 800×600 or 1024×768 on one or both monitors when unlocking in the morning.  Sometimes it would happen in the middle of the day.  Changing the resolution back would sometimes work but often wouldn’t let me set it higher than 1600×1200.  One common denominator seemed to be if a lot of memory was currently in use (e.g. by the database app I’m developing, Visual Studio, Internet Explorer 7, Outlook, etc.).  In those cases it was more likely to happen and more unlikely to be able to fix it.

After a brief search on the Internet, I found several references to the Transient Multi-Monitor Manager.  This is an application that is started by Task Scheduler to make it easier for mobile PCs to reconfigure their displays when plugging external monitors into them.  The workaround suggested in several places is to disable the task.  An especially good article was made by netsaber.

Here are the steps to disable the Transient Multi-Monitor Manager Task:

  1. Open Task Scheduler
    • Start
    • All Programs
    • Accessories
    • System Tools
    • Task Scheduler
  2. Navigate to the MobilePC node in Task Scheduler
    • Task Scheduler Library
    • Microsoft
    • Windows
    • MobilePC
  3. Highlight TMM in the center pane.
  4. Click End in the lower-right pane.
  5. Wait for the status of the TMM task to change to Ready.
  6. Click Disable in the lower-right pane.
vista-tmm.jpg

UPDATE 26-Jun-2008:

When I logged in to my machine this morning the resolution my second monitor was set to 800×600.  I guess disabling this task doesn’t completely fix the problem.  If you find a solution, please post it in the comments.

UPDATE 25-Jul-2008:

I haven’t had any trouble since my last update.  Everything is working great and my resolution has been stable with no resets.