Error Running React Native App From Terminal (iOS)

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I am following the tutorial on the official React Native website.

Using the following to build my project:

react-native run-ios

I get the error:

Found Xcode project TestProject.xcodeproj
xcrun: error: unable to find utility "instruments", not a developer   
tool or in PATH

Command failed: xcrun instruments -s
xcrun: error: unable to find utility "instruments", not a developer 
tool or in PATH

Although, when I run the app from the .xcodeproj, everything works fine.

Any suggestions?

Check out this link: https://github.com/facebook/react-native/issues/7965. It appears to be a problem with the location of Command line tools.

In Xcode, select Xcode menu, then Preferences, then Locations tab. Select your Xcode version from the dropdown and exit Xcode.

You may need to install or set the location of the Xcode Command Line Tools.

Via command line

If you have Xcode downloaded you can run the following to set the path:

sudo xcode-select -s /Applications/Xcode.app

If the command line tools haven't been installed yet, you may need to run this first:

xcode-select --install

You may need to accept the Xcode license before installing command line tools:

sudo xcodebuild -license accept

Via Xcode

Or adjust the Command Line Tools setting via Xcode (Xcode > Preferences > Locations):

I had to accept the XCode license after my first install before I could run it. You can run the following to get the license prompt via command line. You have to type agree and confirm as well.

sudo xcodebuild -license

In my case the problem was that Xcode was not installed.

By default, after installing Xcode command-line not selected, so open Xcode and go to Preferences >> Locations and set Command Line Tools...

This worked for me in MAC High Sierra, Xcode Version 9.3:

Press i to open iOS emulator...

And You can see a cool new iPhone simulator like below image:

For those like me who come to this page with this problem after updating Xcode but don't have an issue with the location setting, restarting my computer did the trick.

For me, it turns out that there was an iOS system update pending asking to restart the computer. Restart and let the update finish solved my problem.

In my case the SDKROOT environment variable was wrong, which referred to an old version of iPhoneOSxx.x.sdk. (Perhaps this would have automatically resolved itself after a reboot?)

You can check by running echo $SDKROOT and verifying that it's a valid path.

I fixed it by updating in .bash_profile:

export SDKROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.2.sdk

Just to document another case: I had Xcode all setup and working, but some command or script had somehow made Xcode to forget command line tools :(

Had to open Xcode and go to settings. There was no command line tools selected, so I had to select it again. The only existing version.

I had a similar issue. Selecting the Xcode version from Xcode> Preferences > Locations - Command Line Tools fixed the issue!

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