The issue is resolved, but now I get this error - not sure if it is related or a new issue.

The issue is resolved, but now I get this error - not sure if it is related or a new issue.
Error: Command failed: xcrun simctl list --json

$ ionic cordova build ios
> ionic-v1 build
[12:49:26] Cannot run sass task: missing in gulpfile.js
> cordova build ios
Running command: /Users/dev/mobileapp/hooks/after_prepare/010_add_platform_class.js /Users/dev/mobileapp
add to body class: platform-ios
(node:62271) UnhandledPromiseRejectionWarning: Error: Command failed: xcrun simctl list --json
dyld: Symbol not found: _SimDeviceBootKeyDisabledJobs
Referenced from: /Applications/Xcode.app/Contents/Developer/usr/bin/simctl
Expected in: /Library/Developer/PrivateFrameworks/CoreSimulator.framework/Versions/A/CoreSimulator
in /Applications/Xcode.app/Contents/Developer/usr/bin/simctl

at ChildProcess.exithandler (child_process.js:291:12)
at ChildProcess.emit (events.js:182:13)
at maybeClose (internal/child_process.js:961:16)
at Socket.stream.socket.on (internal/child_process.js:380:11)
at Socket.emit (events.js:182:13)
at Pipe._handle.close (net.js:599:12)

_Originally posted by @dave-k in https://github.com/ionic-team/ionic-cli/issues/3462#issuecomment-409702069_

Start with the reported `ionic cordova build ios` invocation and the `xcrun simctl list --json` failure, including the `after_prepare/010_add_platform_class.js` hook output. No repository files or tests are named; determine whether this is reproducible in ionic-cli and whether the reported failure is an ionic-cli issue or an environment-related problem.

索引モデルが issue の本文から書いたものです。