Taken from http://blog.zortrium.net/archives/42/comment-page-1#comment-5
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Ever since Macs made the switch to Intel processors and made it easily possible to run Windows applications, I've taken the opportunity to play some classic PC games that never made it to the Mac. One of these is Planescape: Torment, an RPG with a unique setting and great story (a feature sadly often lacking from more modern titles). I started playing it around a year and a half ago through Crossover Games, which in addition to not requiring a reboot, doesn't even need Windows. PS:T worked flawlessly in Crossover (both on my iMac and MacBook) until Apple issued the Mac OS X 10.5.6 update, which included new graphics drivers that completely broke the game -- I (and everyone else playing through Crossover) couldn't even get to the title screen without the game complaining about a bad resolution or color depth and crashing.
Seeing as I was only about a third of the way into the game when this happened, I tried pretty extensively to get the game running again. My Boot Camp installation (Vista at the time) ran the game but had weird graphical glitches on the spell effects as a result of modern graphics drivers, and I didn't really want to have to reboot anyways. VMware Fusion 3 running either Windows 7 or XP also runs the game but exhibits an extremely annoying cursor and animation flicker (I've encountered this flicker in other apps on Fusion 3 that worked great in Fusion 2, and it's one of the reasons I'm not very impressed with v.3 compared to v.2 -- but that's a rant for another time). I also tried in Parallels, which thankfully didn't have any of the aforementioned graphical glitches, but unfortunately also exhibited constant sound glitches including pops and crackles.
Last night I came across my CDs again, decided to take one more whack at it, and, to my suprise, managed to get the game running nearly perfectly in an up-to-date Crossover Games (8.1.4) on a brand-new 27" iMac running Mac OS X 10.6.2. For anyone else frustrated by being unable to get this game running, here's how I did it:
First, we have to install the game and a whole bunch of community mods. These mods do a variety of nice things like making the game run in modern widescreen resolutions, fixing a pile of bugs not fixed by the official patch, and both adding and expanding game content. All good stuff that you should be installing anyways because it gives PS:T a lot of much-needed polish, but in this case, we'll also need them to get the game to run at all. To do the installation and modding, follow this very detailed PS:T installation guide, with a few caveats:
One you've gotten your modded installation set up in Crossover, there's one more obstacle to overcome -- you have to set your monitor to thousands of colors or Planescape will error out on launch. The problem here is that the Displays preference pane in Snow Leopard no longer lets you change the color depth from Millions. To fix this, we need to install the SwitchResX tool, which will let us change to thousands of colors. The option we want in this utility is a bit hidden -- first go to the Menus tab of the SwitchResX Preferences, then activate the Menu Extra by checking the box. This makes a SwitchResX menu appear in the Mac OS X top toolbar, which should allow you to select Thousands of Colors.
Almost there. To launch the game, make sure your monitor is at its native resolution, then switch to thousands of colors before launching Crossover Games. If Crossover is already open when you switch, it won't work. After switching and then launching Crossover, you should be able to start Torment from the programs menu, and (fingers crossed) assuming everything worked, Torment should launch without complaining. If you don't have the physical CD in the drive, the game may hassle you -- I worked around that by mounting a disk image of disc 2 in Toast.
I've only tried actually playing the game for a few minutes since getting it running again, but it seems to be perfect -- runs smoothly and no apparent graphical or sound glitches. The one issue I have on my iMac is that the very bottom of the screen is clipped in-game. I suspect that's a result of the UI mods expecting a typical 16x10 resolution rather than the 16x9 resolution of the new iMacs, but I'll either find a workaround or just play on my 16x10 MacBook.