file was built for archive which is not the architecture being linked (i386)

After struggling with this same problem and following all the accepted answers of updating build settings, clearing the linker search path, etc.. I finally discovered an answer that worked for me.

Before building, make sure you select right type (iPhone Simulator) instead of iOS Device. Then rebuild. Otherwise, you're trying to use a library built for an iOS device (arm processor) on a simulator on your mac (i386). Should've been obvious, but wasn't.

Before:

https://i.stack.imgur.com/YnqsV.png

After:

https://i.stack.imgur.com/p2lnm.png

Now, look in the Products group in the Navigator > right click your static library (.a file) > Show in Finder, you'll notice that its in a Debug-iphonesimulator folder instead of Debug-iphoneos. I didn't pay any attention to the folder name originally, or I might have thought of this sooner.

Hope this helps.

Sometimes these types of errors irritates you!

Removing Derived Data Works for me:

Steps to fix

1) In XCODE > Windows > Project > Select your project > Delete derived Data > Quit XCODE and Reopen it > If you get MAC-O-Linker builed failed error > Refere this link > Clean and Build again.

Your libnetUtils.a is being built for a different architecture than your target.

Check the libnetUtils build settings. The architectures that it is being built for and its list of supported architectures must be a (weak) superset of your target's architecture. The complexity here is that the resulting architecture is spread over various settings: "Architectures", "Build active architecture only" and "Valid Architectures".

"Build active architecture only" settings make this particularly confusing. For example, suppose you are building for the simulator. If the "Build active architecture only" setting for Debug is set to NO, it will be building all the architectures listed in "Architectures" and "Valid architectures" (probably armv7, etc). But if libnetUtils has that setting set to Yes (Debug: Yes) it is only building for i386. So when your linker tries to link armv7 with i386, it fails.

If I get the ignore file warning - I would run lipo -info on ignored file to find it's architecture as below

lipo -info libnetUtils.a

That would print either of i386, armv6, armv7, armv7s, x86_64 etc. In general, that architecture has to match with your target build platform. E.g.

i386 = ios simulator or 32 bit build on mac os x

armv6 armv7 arm7s = ios device

x86_64 = 64 bit build on mac os x

Depending on the mismatch, either you have to rebuild your library for your target platform or change your target platform.

Note: For fat binaries, lipo -info will print a combination of above architectures.

I don't actually know if my advice is correct, but try checking this:

Select your project

Select "Build Settings"

Check Architectures: Valid architectures should be "armv6 armv7" Supported platforms should be "iphonesimulator iphoneos" (maybe iPad, I don't know) Base SDK – your iOS SDK (I have iOS 5.0).

Valid architectures should be "armv6 armv7"

Supported platforms should be "iphonesimulator iphoneos" (maybe iPad, I don't know)

Base SDK – your iOS SDK (I have iOS 5.0).

Do not judge me if I am captain obvious :)

It means the library you are trying to use was not universally compiled for the iOS simulator (i386 symbols are for the Mac). Running it on an actual device should work fine though.

You should also check if Deployment Target within Build Settings is the same for dependant and dependency. I noticed that I had iOS 13 being set for a static library target, while iOS 10.0 was defined for a framework that consumes that library. Switchin both to 10.0 resolved the issue.

Had the same problem, and tried diverse solutions from the page to no avail. I still had a message telling me my library was not build for arm64.

Finally how I resolved it :

opened the project.pbxproj for the library in a text editor

searched for VALID_ARCHS

there were 4 occurrences, 2 of which did not contain arm64

I manually added arm64 in the chain (VALID_ARCHS = "arm64 i386 armv7 armv7s")

rebuild the lib and it was all right

Seems sometimes the build settings displayed by XCode is incomplete, and doesn't correspond precisely to the project file.

To me it was fixed setting the Build Active Architecture Only to Multiple values, to do that, you have to expand it and set Debug to YES and Release to No. And now, it compiles on my device.

This issue will not occur when we run the application on device. You can check it by running the code on iOS device.

I had an architecture of armv7s as well. I deleted it and made sure the armv6 and armv7 were the only two listed. It works now