title: Could not build module 'UIKit' on simulator but not on phone
body: <p>I received following errors when trying to build my project on iphone simulator 5 and 6 and 6 plus. I tried to clean and rebuild again but did not work. I had no clue why this is happening. Because when I plug my phone in, it will run correctly on the phone.</p>
  
  <p>The most important errors here are somehow <code>UIKit</code> and <code>QuarztCore</code> both unfounded.</p>
  
  <p>Can anyone look into this? How do I resolve this issue so that I can run my app on simulator! Thank you!</p>
  
  <pre><code>/project-folder/QuartzCore.framework/Headers/CAMetalLayer.h:7:9: 'Metal/MTLPixelFormat.h' file not found   
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/System/Library/Frameworks/UIKit.framework/Headers/UICollectionViewLayout.h:11:9: Could not build module 'QuartzCore' 
  /project-folder/Parse.framework/Headers/PFConstants.h:27:9: Could not build module 'UIKit' 
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/System/Library/Frameworks/StoreKit.framework/Headers/SKStoreProductViewController.h 
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/System/Library/Frameworks/StoreKit.framework/Headers/SKStoreProductViewController.h:9:9: Could not build module 'UIKit' 
  /project-folder/hatchpic-Bridging-Header.h:8:9: Could not build module 'Parse' Failed to import bridging header 
  '/project-folder/hatchpic-Bridging-Header.h' Failed to import bridging header 
  '/project-folder/hatchpic-Bridging-Header.h' Command failed due to signal: Segmentation fault: 11
  </code></pre>