<p dir="auto">'flutter doctor' worked correctly it suggested I update so then<br>
I ran 'flutter upgrade' as well as updating my macos and xcode. Then ran xcode and which installed additional updates.</p>
<p dir="auto">Karls-MBP-2:~ karllilley$ flutter doctor -v<br>
[✓] Flutter (Channel beta, v0.2.3, on Mac OS X 10.13.4 17E199, locale en-US)<br>
• Flutter version 0.2.3 at /Users/karllilley/flutter<br>
• Framework revision <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https://github.com/flutter/flutter/commit/5a58b36e36b8d7aace89d3950e6deb307956a6a0/hovercard" href="https://github.com/flutter/flutter/commit/5a58b36e36b8d7aace89d3950e6deb307956a6a0"><tt>5a58b36</tt></a> (3 weeks ago), 2018-03-13 13:20:13 -0700<br>
• Engine revision <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https://github.com/flutter/flutter/commit/e61bb9ac3a3fd789754e2e54220bcfc27076a857/hovercard" href="https://github.com/flutter/flutter/commit/e61bb9ac3a3fd789754e2e54220bcfc27076a857"><tt>e61bb9a</tt></a><br>
• Dart version 2.0.0-dev.35.flutter-290c576264</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Oops; flutter has exited unexpectedly.
Sending crash report to Google.
Crash report sent (report ID: 11ccd05f01dbb253)
Unhandled exception:
NoSuchMethodError: The method 'run' was called on null.
Receiver: null
Tried calling: run(Instance(length:2) of '_GrowableList', environment: null, workingDirectory: null)
#0      Object.noSuchMethod (dart:core-patch/dart:core/object_patch.dart:46)
#1      runAsync (package:flutter_tools/src/base/process.dart:227)
&lt;asynchronous suspension&gt;
#2      IOSWorkflow.macDevMode (package:flutter_tools/src/ios/ios_workflow.dart:45)
&lt;asynchronous suspension&gt;
#3      IOSWorkflow.validate (package:flutter_tools/src/ios/ios_workflow.dart:90)
&lt;asynchronous suspension&gt;
#4      Doctor.startValidatorTasks (package:flutter_tools/src/doctor.dart:71)
#5      Doctor.diagnose (package:flutter_tools/src/doctor.dart:128)
&lt;asynchronous suspension&gt;
#6      _doctorText.&lt;anonymous closure&gt; (package:flutter_tools/runner.dart:237)
#7      AppContext._run (package:flutter_tools/src/base/context.dart:76)
&lt;asynchronous suspension&gt;
#8      AppContext.runInZone.&lt;anonymous closure&gt; (package:flutter_tools/src/base/context.dart:66)
#9      _rootRun (dart:async/zone.dart:1126)
#10     _CustomZone.run (dart:async/zone.dart:1023)
#11     runZoned (dart:async/zone.dart:1501)
#12     AppContext.runInZone (package:flutter_tools/src/base/context.dart:65)
#13     _doctorText (package:flutter_tools/runner.dart:237)
&lt;asynchronous suspension&gt;
#14     _createLocalCrashReport (package:flutter_tools/runner.dart:212)
&lt;asynchronous suspension&gt;
#15     _handleToolError (package:flutter_tools/runner.dart:167)
&lt;asynchronous suspension&gt;
#16     run.&lt;anonymous closure&gt; (package:flutter_tools/runner.dart:94)
&lt;asynchronous suspension&gt;
#17     AppContext._run (package:flutter_tools/src/base/context.dart:76)
&lt;asynchronous suspension&gt;
#18     AppContext.runInZone.&lt;anonymous closure&gt; (package:flutter_tools/src/base/context.dart:66)
#19     _rootRun (dart:async/zone.dart:1126)
#20     _CustomZone.run (dart:async/zone.dart:1023)
#21     runZoned (dart:async/zone.dart:1501)
#22     AppContext.runInZone (package:flutter_tools/src/base/context.dart:65)
#23     run (package:flutter_tools/runner.dart:61)
&lt;asynchronous suspension&gt;
#24     main (package:flutter_tools/executable.dart:48)
&lt;asynchronous suspension&gt;
#25     main (file:///Users/karllilley/flutter/packages/flutter_tools/bin/flutter_tools.dart:16)
#26     _startIsolate.&lt;anonymous closure&gt; (dart:isolate-patch/dart:isolate/isolate_patch.dart:277)
#27     _RawReceivePortImpl._handleMessage (dart:isolate-patch/dart:isolate/isolate_patch.dart:165)"><pre class="notranslate"><code class="notranslate">Oops; flutter has exited unexpectedly.
Sending crash report to Google.
Crash report sent (report ID: 11ccd05f01dbb253)
Unhandled exception:
NoSuchMethodError: The method 'run' was called on null.
Receiver: null
Tried calling: run(Instance(length:2) of '_GrowableList', environment: null, workingDirectory: null)
#0      Object.noSuchMethod (dart:core-patch/dart:core/object_patch.dart:46)
#1      runAsync (package:flutter_tools/src/base/process.dart:227)
&lt;asynchronous suspension&gt;
#2      IOSWorkflow.macDevMode (package:flutter_tools/src/ios/ios_workflow.dart:45)
&lt;asynchronous suspension&gt;
#3      IOSWorkflow.validate (package:flutter_tools/src/ios/ios_workflow.dart:90)
&lt;asynchronous suspension&gt;
#4      Doctor.startValidatorTasks (package:flutter_tools/src/doctor.dart:71)
#5      Doctor.diagnose (package:flutter_tools/src/doctor.dart:128)
&lt;asynchronous suspension&gt;
#6      _doctorText.&lt;anonymous closure&gt; (package:flutter_tools/runner.dart:237)
#7      AppContext._run (package:flutter_tools/src/base/context.dart:76)
&lt;asynchronous suspension&gt;
#8      AppContext.runInZone.&lt;anonymous closure&gt; (package:flutter_tools/src/base/context.dart:66)
#9      _rootRun (dart:async/zone.dart:1126)
#10     _CustomZone.run (dart:async/zone.dart:1023)
#11     runZoned (dart:async/zone.dart:1501)
#12     AppContext.runInZone (package:flutter_tools/src/base/context.dart:65)
#13     _doctorText (package:flutter_tools/runner.dart:237)
&lt;asynchronous suspension&gt;
#14     _createLocalCrashReport (package:flutter_tools/runner.dart:212)
&lt;asynchronous suspension&gt;
#15     _handleToolError (package:flutter_tools/runner.dart:167)
&lt;asynchronous suspension&gt;
#16     run.&lt;anonymous closure&gt; (package:flutter_tools/runner.dart:94)
&lt;asynchronous suspension&gt;
#17     AppContext._run (package:flutter_tools/src/base/context.dart:76)
&lt;asynchronous suspension&gt;
#18     AppContext.runInZone.&lt;anonymous closure&gt; (package:flutter_tools/src/base/context.dart:66)
#19     _rootRun (dart:async/zone.dart:1126)
#20     _CustomZone.run (dart:async/zone.dart:1023)
#21     runZoned (dart:async/zone.dart:1501)
#22     AppContext.runInZone (package:flutter_tools/src/base/context.dart:65)
#23     run (package:flutter_tools/runner.dart:61)
&lt;asynchronous suspension&gt;
#24     main (package:flutter_tools/executable.dart:48)
&lt;asynchronous suspension&gt;
#25     main (file:///Users/karllilley/flutter/packages/flutter_tools/bin/flutter_tools.dart:16)
#26     _startIsolate.&lt;anonymous closure&gt; (dart:isolate-patch/dart:isolate/isolate_patch.dart:277)
#27     _RawReceivePortImpl._handleMessage (dart:isolate-patch/dart:isolate/isolate_patch.dart:165)
</code></pre></div>
<p dir="auto">Our console output when running xCode builds is very noisy and hard to read. We heard very good things about <a href="https://github.com/supermarin/xcpretty">https://github.com/supermarin/xcpretty</a> from another team that runs xCode builds, so would be good to give that a try for Flutter.</p>