I have an ATEN CS1732B KVM switch and I had a desktop PC running windows 7 and a MacBook Pro (2008) running MAC OSX 10.7.5 (lion) connected to it and they both ran fine. I got the full resolution from my 24" monitor of 1920x1080 using both computers and they switched perfectly.

CS1732B - 2-Port USB 2.0 KVMP? Switch with OSD

I specifically chose this model as it had the EDID Video DataSync feature.

I have just upgraded my MacBook Pro to a new 13" (2012) model running MAC OSX 10.8.2 (mountain lion), but when I connect this through the KVM, it switches between computers fine, mouse and keyboard work, but I can't get the full resolution of 1920x1080, the maximum I can get is the MacBook Pro's native 1280x800 and the display is all stretched and flickering.

The old MacBook Pro connects to the VGA cable with a DVI to VGA adaptor and the new MacBook Pro connects using a mini display port to VGA adaptor. If I use this adaptor to connect directly to the monitor and bypass the KVM it works fine and I can get the full resolution, so it appears there is a problem getting the signal through the KVM which is strange as it worked with the other MacBook Pro.

Anyone had any similar issues with a newer MacBook Pro and a KVM? Would it be hardware or mountain lion related?

Thank you!