My app was running perfectly without any errors or warnings yesterday. But when I tried to run it today, the build failed - I haven't changed anything in the code:

Undefined symbol: __swift_FORCE_LOAD_$_XCTestSwiftSupport

How to fix this, and why would something like this occur suddenly when it was working before?

And this is an issue I've been experiencing with XCode a lot lately. My code will be running smoothly without any errors, but then XCode will randomly start throwing errors when I relaunch it at a different time - without making any changes in the actual code.

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CodePudding user response：

I solved this error by navigation to target app settings > Build Phases > Link Binary With Libraries > add the linked library "XCTest.framework".

If afterwards your app starts crashing, aborting the following errors:

dyld: Library not loaded: @rpath/XCTest.framework/Versions/A/XCTest

0_abort_with_payload

This thread includes several suggestions: Xcode 5.0.2 dyld: Library not loaded: @rpath/XCTest.framework/Versions/A/XCTest

The solution that worked for me was: Navigate to target app > Build Settings > Linking > Other Linker Flags > editing or adding -weak_framework "XCTest"