CODEWITHSUNDEEP
iosxcodereact-nativeexposimulator
Archit Kithania
Archit Kithania

Reputation: 307

How to fix expo start throwing "Simulator is installed but is identified as 'com.apple.CoreSimulator.SimulatorTrampoline'; dont know what that is"

I am trying to set up a react-native development environment. I would like to set up an iOS emulator (preferably an iPhone 10) to run my app on. I am using a Macbook Pro 2016 running on MacOS 10.14.3. I have installed my react-native app through the command create-react-native-app (running version 2.0.2). I also have installed XCode running version 10.2(10E125). When I scan the QR code that Expo generates and run it on my iPad or my Android device it works just fine, but when I try to load the iOS emulator by pressing i after expo start it returns the error 

Trying to open the project in iOS simulator...
Simulator is installed but is identified as 'com.apple.CoreSimulator.SimulatorTrampoline'; don't know what that is.
Simulator not installed. Please visit https://developer.apple.com/xcode/download/ to download Xcode and the iOS simulator. If you already have the latest version of Xcode installed, you may have to run the command `sudo xcode-select -s /Applications/Xcode.app`

I have already tried running the command sudo xcode-select -s /Applications/Xcode.app

I have also tried running the command xcode-select -r

I have also confirmed that in my XCode->Preferences->Locations Command Line Tools is selected as "Xcode 10.2(10E125)"

None of these have worked.

I am expecting that after pressing i after expo start an iOS emulator loads up. Thank you.

-----EDIT-------

After some more research, I found out that running open -a Simulator and then running expo start loads the app on an emulator and works for my purposes. But still if I just run expo start without running open -a Simulator it still gives the same error. I want to ask if this is the best I am going to get?

Upvotes: 4

Views: 2626

Answers (2)

Ben Butterworth
Ben Butterworth

Reputation: 28478

You might be running an outdated version of Expo. I had this problem when I was download someone's old repo using Expo 27 when Expo 36 came out. After updating to the latest version, it works.

To update packages in your project, npm-check-updates comes in handy. 

npm i -g npm-check-updates # installs ncu globally
ncu -u # updates all dependency versions in your local package.json
npm install # updates the packages in node_modules to match

Note: This will update all your dependencies to the latest version. If you don't want to do this, you can find the latest version of expo and change the version in package.json manually.

Upvotes: 3

ChrisF582
ChrisF582

Reputation: 171

I ran into the exact same problem all of a sudden. Clicking "Run on iOS Simulator" within the Expo Developer Browser worked 2 days ago but did not work today. Your clue of using open -a Simulator helped me though. I went into Xcode and clicked the Xcode menu > Open Developer Tool > Simulator. This started the Simulator and then I was able to click "Run on iOS Simulator" within the Expo Developer Browser and it worked as expected. If you haven't had the fortune of "Run on iOS Simulator" working, I'm guessing you could just start a simulator, download Expo from the App Store and just use it from there. None of this answers the question as to why the error happens but at least gives a few workarounds for anyone else that might need. All that matters is you get the app running on the Simulator in the end!

Upvotes: 1

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