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I'm working on a project for iOS and I'm doing the programming with Visual Studios and it connects to a mac server using Xamarin. I recently tried to add more views to the storyboard and an additional class. When I tried to build the code, I received this error. http://pastebin.com/Ub5s89aa This is what the output from the console. http://pastebin.com/fhWDy2cJ

I don't know what this error means and when I tried to look up any part of the error, nothing helped. I cleaned my builded and tried to rebuild, and I also closed Visual Studios and reopen it to see if that help, but it didn't. Has anyone else had this problem before?

Adam Lietzau
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  • Was there something you changed in the code that caused this problem to start happening, or have you never been able to build the code? – BradzTech Apr 10 '16 at 18:29
  • I was able to build the code before. I recently added two table view controllers and a class. When I removed both, it did not fix the issue. – Adam Lietzau Apr 10 '16 at 18:32
  • Try cleaning your project, deleting derived data, and ensure there are no unconnected IBOutlets. Also make sure you didn't accidentally change anything in your app's build settings; the error you posted seems to have something to do with architecture inconsistency. – BradzTech Apr 10 '16 at 18:36
  • I wasn't able to find out what the exact issue was. I talked to my professor and he things it might have been an unconnected IBOutlet like you mention. I rolled back my project to before I made the changes and it works so far. I will make sure to be testing my builds before I make major edits like I did and I will post if the error comes up again. – Adam Lietzau Apr 10 '16 at 19:58

12 Answers12

587

Restarting the CoreSimulatorService solved the issue on my machine.

sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
riik
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    This happened to me with the latest Xcode 10.3 (10G8) release, and this answer resolved the issue. Thanks! – Scott Gardner Jul 25 '19 at 17:13
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    I had the same problem after I upgrade my `Xcode` to `version: 10.3.` **Open terminal and run:** sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService Then do a Clean Build folder and the error is gone. – Enea Dume Jul 25 '19 at 12:23
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    Yep, worked for me... had this issue after upgrading to the latest XCode (10.13 10G8) & Mojave (10.14.6). – Sam Grant Jul 29 '19 at 15:18
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    Worked for me too! Got the same error after upgrading XCode from 10.2 to 10.3 (10G8), using macOS Mojave 10.14.5 (18F132) – Mike Jul 30 '19 at 11:24
  • I can confirm it worked under quasar dev mode cordova on Max 10.14.6 and Xocde 10.13. Even in my case the problem happened after upgrading Xcode – realtebo Jul 30 '19 at 20:39
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    I think that saved a lot of developers a lot of headache! Thanks for sharing that information with us! – randomcontrol Jul 31 '19 at 19:30
  • riik you're a god. was building from Unity and thought for sure I was in for a long night (the interaction can be quirky between Unity/Xcode). this was an immediate fix. fastest solution I've had in 7 years on stackoverflow. well done. – Jon K Aug 05 '19 at 02:18
  • Went from Xcode 10.1 to 10.3 and got this same error as well, thought it was something to do with React Native code or the macOS version (10.14.5). Solution works. – CyberMew Aug 07 '19 at 06:56
  • I had same problem after setting up Flutter for iOS. This solution fixed problem. Thank you. – slobodans Aug 08 '19 at 14:06
  • This issue happen after I upgrade the Xcode version, the resolution is works! – Cheung Aug 27 '19 at 07:14
  • Wow, thanks for this answer! It solved the problem! I also had upgraded to 10.3 when it happened. – Lucy Oct 20 '19 at 12:14
  • For me I also had to restart XCode. Just a note for others – dragonfire Nov 13 '20 at 18:46
  • I've ignored this answer, because don't use simulator at all. However apparently it still can break my build. I flipping love XCode – Dmytro Rostopira May 05 '21 at 10:37
150

I had the same problem after I upgrade my Xcode to version 10.3.

I just restart my Mac and problem solved!

Hope this would work with you too :)

Sunil Targe
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Mine happened when updating to Xcode 10.3

X-code helper didn't get the permission to control the computer.

This is what i did to solve the problem

System Preference > Security&Privacy > privacy tab > accessibility

give permission for 'Xcode Helper'

Restart X-code and kill all simulators like @riik stated

sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
Nic Wanavit
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9

This issue is with xcode update 10.3 and mixpannel is gives this as build error

Steps to fix.

Open terminal and paste this

sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService

Clean Xcode and build. Thats all

Subodh Kumar
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After having a google I found a similar question here and here, summary of the some of the answers in that question:

  • Make sure you are running the latest version of Xcode and you dont have a beta installed.
  • Close Xcode and then opened up Activity Monitor. Terminate any Ibtool processes running and restart Xcode.
  • Delete any custom color pickers you have installed in for Xcode, close the Xcode and relaunch
  • Try recreating any nibs you may have changed.

summary from the Xamarin Forums link:

Uninstall Xamarin studio, Xcode
Delete /Libraries/Developer and ~/Libraries/Developer folders
Reboot
Reinstall Xcode, Xamarin studio

If none of these work could you check in the Console.app for any errors when building.

Hope this helps.

Community
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Iain Smith
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I got this error after installing Xcode 12 beta. Restarting my Mac did not fix the problem. I had to reinstall Command Line Tools:

  • delete /Library/Developer (note this is the root Library directory, not ~/Library);
  • launch Xcode and let it install Command Line Tools.
Vladimir Grigorov
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  • I have experienced the same issue since upgrading to Xcode 12.5: Restarting Mac and restarting CoreSimulatorService did not work, but reinstalling Command Line Tools as described in the answer worked – JRV May 19 '21 at 06:49
  • Xcode 13.4, this worked for me, the other answers did not. – Carlos De la Mora May 28 '22 at 21:53
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I had my Xcode files on an external drive in User/Library/Developer/CoreSimulator. The issue was fixed upon doing the command sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService then moving these developer files back onto the mac.

Connors Apps
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I fixed same issue by restart mac and rebuild project. CMD + B!

Malik Hassnain
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None of these other solutions worked for me, unfortunately. After hours of digging, I discovered I had to reset the read/write permissions in my home folder.

ultraprotean
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For me the issue was caused by the build getting executed by a launch daemon (on a CI server) without a user being logged in. Switching to a launch agent that is run when the user is logged in fixed the issue.

Frederik
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We recently had this issue after upgrading to Xcode 12 on our CI machine. Turn out we did not launched Xcode prior to using xcodebuild commands.

  • Launch Xcode and let it install Command Line Tools solved this.

Hope this help somebody

BenBenMushi
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I solved this error and other weird build errors to which the standard recommendations of this site did not solve, by moving my project from external SSD to internal disk. My advice never put your projects on external disks while you are working on them at least.

7RedBits.com
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