External monitor resolution setting is lost after MacBook "wakes up" from sleep I have recently purchased an external monitor that I am connecting to my MacBook Pro (Late 2009) using the MiniDisplay-to-VGA adapter. I have both the external monitor and the MacBook's monitor set to "Best Available" resolution in OS X Lion. Whenever the computer "wakes up" from its sleeping state, the resolution setting for the external monitor is "forgotten". Every time the computer "wakes up", the resolution of the external monitor is set to match the MacBook's monitor. 

The only reason I am using the VGA cable rather than a DVI cable, is because I do not have the MiniDisplay-to-DVI adapter. Will switching to DVI solve the problem? Is there any known way to solve this issue other than getting a utility to reset the resolution manually every time? 

Thanks.
I recommend you reset your NVRAM. This chip stores information on screen resolution and can often become corrupted. You can reset it by starting your Mac while holding down cmd + opt + P + R . You should hear the Mac chime, restart and chime a second time. Then you can release the keys you are holding. More info here.