react-native run-ios doesn't run: Application is unknown to FrontBoard?

Question

I had react-native run-ios working for the past few days but today it randomly decided to stop working:

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The following commands produced analyzer issues:
    Analyze /Users/swyx/Desktop/webdev/fullstacksr/reactNativeExtensions/ActionExtensionExample3/node_modules/react-native/ReactCommon/yoga/yoga/YGNodeList.c
    Analyze /Users/swyx/Desktop/webdev/fullstacksr/reactNativeExtensions/ActionExtensionExample3/node_modules/react-native/ReactCommon/yoga/yoga/Yoga.c
(2 commands with analyzer issues)

Installing build/Build/Products/Debug-iphonesimulator/ActionExtensionExample3.app
An error was encountered processing the command (domain=IXErrorDomain, code=2):
Failed to set plugin placeholders for org.reactjs.native.example.ShareExtensionExampleswyx
Launching org.reactjs.native.example.ShareExtensionExampleswyx
org.reactjs.native.example.ShareExtensionExampleswyx: -1
An error was encountered processing the command (domain=FBSOpenApplicationServiceErrorDomain, code=1):
The request to open "org.reactjs.native.example.ShareExtensionExampleswyx" failed.
The request was denied by service delegate (SBMainWorkspace) for reason: NotFound ("Application "org.reactjs.native.example.ShareExtensionExampleswyx" is unknown to FrontBoard").

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Possible causes and solutions investigated:

• Checking the scheme - it is definitely Ask on launch
• Scheme settings - i dont have any empty settings to leave unchecked
• Maximum App ID limit reached - this app id org.reactjs.native.example.ShareExtensionExampleswyx is something I am reusing but i dont think it causes this issue
• deleting ios/build and recompiling
• restarting my simulator and my entire computer
• Edit: yes i am using xcode 9

none of these have worked so far. Any other ideas on things to try please?

Answer 1

As mentioned by Gavin Owens on Github, I followed those steps and it worked.

Just delete ios/build from iOS directory and after that run command react-native-run-ios

use following command

rm -rf ios/build then running react-native run-ios

Answer 2

try with another simulator if it works you need to reset your simulator from simulator menu

1. Simulator -> Reset Content And Setting if you have Xcode 9 it will be from Hardware -> Erase All Content and Settings
2. clean from Xcode menu Product -> Clean and run your project