Availability.h, UIKit.h, etc not found

Question

I\'m having a great problem here.

I recently downloaded Xcode 4.3 from the Mac App Store, because it had the full-screen feature for Lion. And then, my project stopp

Answer 1

I just had a similar issue.

I had added one of my own .h files to the .pch so I didn't have to import it into every class. It was fine until just now when I started to get errors but only when building for a device. The weird thing is that it anyway installed and ran ok on the device and there were never any errors at all on the simulator.

All I did was delete the import line from the .pch, cmd+S and then tapped my heels together three times and added it back.

I did an option+clean and then it compiled with no problems at all. Very happy to not have to reinstall Xcode and perhaps this will help someone else?

Answer 2

I try delete and reinstall Xcode it's work. Thank.

Answer 3

UIKit is not for Lion but limited to iOS. Is your project targetting iOS SDK?

Answer 4

Removing the project completely and adding everything again has worked for me several times.

Answer 5

I hate this problem! There seems to be a simple solution that SOMETIMES works:

Possible solution

Go to Build Phases -> Link Binary With Liibraries.

If you are having a problem with say Foundation.framework. Simply delete that one --- i.e., use the minus ("-") button at the bottom of the list.

And then add it again, using the plus button.

Clean the build folder. (To do so hold down ALT, then click Product -> Clean. You will see "Clean" changes to "Clean Build Folder")

Another possible solution

Be sure to read Matthew's answer here ...

iOS SDK broken ever after reinstall UIKit and Foundation frameworks not found

Look at the value of your "Framework Search Paths".

Another possible solution

Completely and totally uninstall XCode 4.3, use "CleanMyMac" to do so (it will try to find every associated component of the app you are trying to delete).

Then just use the App Store to (re) install XCode. As David mentions, this can sometimes fix this damn problem.

Why does it happen?...

I believe this problem can possibly happen in situations where you have, say, replaced your hard drive (i.e., probably using Carbon Copy Cloner or the like) or in some way the main volume on your Mac gets renamed or changed in some way. I think there might be a slight bug in the new "application-style" Xcode where it sometimes does and sometimes does not understand that sort of change in the paths.

I hope it helps someone!

It is an infuriating problem. I just had it happen again, in this case, because I subsequently deleted a copy of the "old-style" XCode from a machine. (It's perhaps better to utterly delete old-style XCodes (/Developer directory, etc) before installing the new-style XCode.)

Answer 6

Check that "Use Standard System Header Directory Searching" (under "Build Settings") is set to Yes.

I accidentally changed that setting and had the same issue also.