Anyone have an idea of how to conditionally use a toolbox that is available in OSX but not in carbon classic AND not have the toolbox checker option give a warning. I'm planning to conditionalize my code to check to see if you are in classic. If you are in classic it will call a standard alert but in OSX - not classic it will use CreateStandardSheet. Unfortunately this will set off the alarm unnecessarily in the toolbox checking routine which is extremely useful. Thanks, W. http://developer.apple.com/carbon/tipsandtricks.html How do I link against symbol like CreateStandardSheet() which is available on Mac OS X but not available on Mac OS 8/9? While Mac OS X continues to evolve, CarbonLib remains a moving target. If you want to take advantage of the very latest Mac OS X technologies not yet being exported by CarbonLib you may want to create your own stub library to link against in addition to CarbonLib. Follow these steps to create a stub library: Create a text file, "MissingCarbonAPIs.exp" whose contents are: # This is a Mac OS X Only API CreateStandardSheet From MPW Type: MakeStub MissingCarbonAPIs.exp -o MissingCarbonAPIs.stub -fragname CarbonLib -weakstub on