184
votes

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?

12
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
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
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
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

12 Answers

581
votes

Restarting the CoreSimulatorService solved the issue on my machine.

sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
149
votes

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 :)

21
votes

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
8
votes

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

4
votes

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.

1
votes

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.

1
votes

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.
0
votes

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

0
votes

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.

0
votes

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.

0
votes

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

0
votes

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.