I installed Xcode 3.1 and the iPhone SDK beta 1 when it was released. I had no problems with it. Apple released beta 2 the other day and I installed that over the top of the previous install. Since then - on both a new 2.8GHz 8-core Mac Pro (Early 2008) and a 2.6GHz C2D 17" MBP SR (Nov 2007) - the iPhone simulator will sometimes fail to launch. When this happens, GDB (the debugger) says it failed to launch the simulator, then I'll be unable to launch ANY application as I get a -10810 error from the Finder. Applications already running continue to run but I can't start any new processes. Once that happens, it's about 20 seconds before everything disappears and I'm thrown back to the login screen. No other software has been installed on these machines other than whatever security updates Apple released, and the new firmware for the Mac Pro. (Given that this is seen on the MBP as well, the firmware cannot have been the cause.) Any ideas? Here's what the Console says: Code: 30/03/2008 15:57:29 [0x0-0x2a02a].com.apple.Xcode Xcode(502,0xb0103000) malloc: free_garbage: garbage ptr = 0x37f08f0, has non-zero refcount = 1 30/03/2008 15:57:56 Xcode !!! _NSGlyphTreeInsertGlyphs invalid char index 30/03/2008 15:57:56 Xcode !!! _NSGlyphTreeSetIntAttributeForGlyphAtIndex invalid glyph index 54471 I'm definitely freeing memory as and when necessary, but I can't see how that might crash the entire system?!