During iOS app development, I encountered an error when building after replacing the external SDK opencv2.framework files.

Error Message

fatal error: 
file '/Users/your_username/git/myapp/./opencv2.framework/Headers/opencv.hpp' 
has been modified since the precompiled header was built
1 error generated.

Solution

Clean and then rebuild - that’s it.

Reference Information

• ios - XCode 4.1 fatal error: stdlib modified since the precompiled header was built - Stack Overflow

That’s all from the Gemba.