Dealing with Missing SDKs in Xcode

If you’re running a recent version of Xcode, you may notice a problem when opening older projects. The Overview pop-up menu in the project window toolbar will tell you the Base SDK is missing. The cause of this problem is the project you opened used a SDK that is not installed on your Mac.

The missing SDK problem is most likely to occur if you have installed the iPhone 4 SDK. The iPhone 4 SDK installation erases any previously installed SDKs so any Xcode projects that use an older version of the iPhone SDK have a missing SDK. The missing SDK problem is not limited to iPhone projects. Mac projects can have the problem as well, but they’re less likely to have the problem because Xcode 3.2 installs the 10.5 and 10.6 SDKs. A Mac project would have to use the 10.4 SDK (or earlier SDK) to get the missing SDK message.

The solution to the missing SDK problem is to set the Base SDK to one that is installed on your Mac. Choose Project > Edit Project Settings to change the Base SDK build setting. For those of you using the iPhone 4 SDK, set the Base SDK to iPhone Device 4.0.

The missing SDK message in the Overview pop-up menu should go away now.

iPhone Device 4.0 is the most recent SDK as I’m writing this post. Use the most recent SDK if you’re reading this post in the future.