Build error Xcode 10 - Multiple commands produce

Question

I just upgraded to Xcode 10, and I suddenly face this error when I try to build, any ideas how to fix it? I tried cleaning derived data, but without any luck.

Solution 1

If you use CocoaPods, click Xcode menu file -> Workspace Settings , And click Build system choice Legacy Build System

If you not use CocoaPods, same of top , select Project Settings

Solution 2

If your app is generating the error related to the multiple .app files just like mentioned above in question then removing the .plist files from "Copy bundle Resources" WILL NOT WORK.

If the error is related to .app file then follow the following steps.

1. Select the Target.

2. Go to Build Phases tab.

3. Remove the items listed in Output Files
4. Compile the code if it compiles successfully then not follow the next steps.
5. If code does not compile successfully and Xcode may give you an error related to "Library not found". Then add the missing library in General Tab in Linked Frameworks and Libraries that Xcode mentioned in the error.

6. Keep adding these libraries (that Xcode ask through compile errors) in Linked Frameworks and Libraries until the code compiles successfully.

   Hope this helps.

Solution 3

You can try to change the build system to Legacy, File > Workspace Settings > Build System > Legacy Build System.

Solution 4

If this is CoreData related. The issue is that you are trying to generate the NSManagedObject subclass but you need to set the 'CodeGen' option to Manual/None. This option is defaulted to Class definition and this would regenerate the code thus creating this issue.

Solution 5

I also faced this issue in xcode 10 but it was because of adding the same framework in main project + other extensions (watchkit or siri extension etc). I added ObjectMapper in podfile for my main project + for my extensions. When I compiled it gave me an error that multiple command produce and also shows me which framework is causing this issue. Now its working fine for me as I've removed it from my extensions I wasn't using it in my extensions.

Don't know about your issue may be you can check your podfile.

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Comments

[XcodeNOOB]

how is cocapods relate to this issue ? I have a project with cocapods on the it's run with the new build system

[Almeida]

I tried it but just this stackoverflow.com/a/52451421/2238515 solved for me

[Deepak Sharma]

This worked for me, but why are we supposed to use 'Legacy build' system? Why can't we use new build system?

[asif saifi]

yes i was facing the same problem. i got the solution with your answer . thanx man

[huggie]

I am using Carthage and this helped. Thank you very much. But what was the problem and why does this even work? Using legacy scares me because I don't know how long until the next version of Xcode is going to swap this out from under me.