I have an early 2007 Macbook Pro running 10.5 that I've recently set up on a KVM with my primary desktop system.
The problem I've run into is that I have a 20" 1680×1050 LCD, and OS X only provides options to mirror at the resolution of the built-in display or to span. Since the built-in display runs at 1440×900, this leads to running my LCD at non-native res and a fuzzy picture. There isn't any option that I can find to simply disable the built-in display entirely and run the external LCD at its native resolution.
I am aware of closed lid mode, but the MBP was disassembled while in storage for about 6 months (took it apart to pull the HDD) and the cable to the touchpad, which controls the sleep sensor was damaged, meaning closed lid mode won't work. I've looked into replacing the cable, but the cheapest I've been able to find it is $75-100, and I'm trying not to invest any more money into this computer as it also has a completely dead battery and a few other minor problems.
I've found the app SwitchResX which appears to allow you to do what I need, but it has a lot of functionality I don't need and a ~$20 registration charge attached to it.
An odd set of circumstances, I'm aware, but I was hoping somebody might know of an OS hack that would let me just disable the internal display and be done with it. 🙂
Best Answer
The easiest fix is in the display arrangement. You can leave the built-in display active, just arrange it so that it's at a corner, and put the menu bar on the external display. You might have to play with the arrangement depending on where you keep the dock. It's a cheap hack, but it sounds like that's what you need(ed).