How to Fix Base SDK Missing Problem in XCode

In this article I cover how you can fix the Base SDK Missing problem you might have had using the iOS SDK 5.2. The video above is easiest to see in full screen mode.

Background:
I downloaded Apple’s iOS SDK 5.2 and installed it on my Mac. After that process was over , I decided to load an existing project of mine into XCode. Ok, good. Then I tried to do a build. Kaboom! It did not work! No worries I thought, I will just go to the drop-down and pick the latest SDK 5.2. But the option was not there! The thought came to me that I might have to create a new project and import all my files from my existing project just to get it to work. Not a very nice thought to say the least!

Unexpected Source for a Solution
Approximately a day later I got a book I ordered called Learn iPhone and iPad Cocos2D Game Development
by Steffen Itterheim. I bought this book with ambitions for writing my own game or two.  Anyway, in chapter 2 “Getting Started” on page 17, the author of the book described the solution to my problem and yours: how to fix this Base SDK Missing problem.

Here are the step by step instructions to fix your project:

1. Load up the project in question into XCode. …   Also notice I highlighted the message in question in green:.
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2. On the XCode menu bar, pick the Project menu option..
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3. The third option from the bottom of the Project menu is Edit Project Settings, pick it..
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4. The Project Info window will appear. There are four tabs at the top: General, Build, Configurations, and Comments. Make sure that the Build tab is selected.
5. The Top Group on this tab is called Architectures. The third item under Architectures is Base SDK. You will see which SDK it was trying to use with the word (missing) next to it.  … Notice below I’ve highlighted the Build tab and have green arrows pointing to the Architectures group, the Base SDK option, and the iOS 4.0 (missing) to have them stand out for you..
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6. Click on the Value column for Base SDK to get the following menu:.
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7. You will notice various SDKs available to you to use. In this case we are not interested in any Mac OS X SDKs, but rather a valid iOS SDK value! The only one available in our example is iOS 4.2 in this case. So, we would pick it!
8. The Base SDK value will now be set to iOS 4.2. (see screen shot below)…  The value is automatically saved to the project so there is no need to do a save.
9. Close the Project Info window. The main project window itself will still be unchanged. It will still say Base SDK missing. Do not freak out! Your changes have taken effect. All you need to do now is close and reopen your project and you will be good to go!