Xamarin, Fix>Error: ibtool exited with code 255

Xamarin.Forms で iOS のプロジェクトをビルドしたら以下のようなエラーが発生しました。

/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(3,3): Error: ibtool exited with code 255 (PrismSample2.iOS)

最初は訳が分からなかったのですが、Xcode のアップデート中だとビルドに失敗する模様。

Xcode のアップデートを最後まで完了させたらエラーは発生しなくなりました。

なお、上記エラー以外にも以下のようなエラーが発生していましたが、こちらも解消しました。

/Users/xxx/Projects/PrismSample2/PrismSample2.iOS/Resources/LaunchScreen.xib: Error: 2018-09-18 22:50:36.285 ibtoold[46678:42176806] +[SimServiceContext serviceContextForDeveloperDir:error:]: unrecognized selector sent to class 0x119e2fc00
2018-09-18 22:50:36.317 ibtoold[46678:42176806] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[SimServiceContext serviceContextForDeveloperDir:error:]: unrecognized selector sent to class 0x119e2fc00'
*** First throw call stack:
(
    0   CoreFoundation                      0x00007fff367a22db __exceptionPreprocess + 171
    1   libobjc.A.dylib                     0x00007fff5d943c76 objc_exception_throw + 48
    2   CoreFoundation                      0x00007fff3683acf4 +[NSObject(NSObject) doesNotRecognizeSelector:] + 132
    3   CoreFoundation                      0x00007fff36718820 ___forwarding___ + 1456
    4   CoreFoundation                      0x00007fff367181e8 _CF_forwarding_prep_0 + 120
    5   IDEInterfaceBuilderCocoaTouchIntegration 0x00000001199bf2dc __IBSharedInterfaceBuilderSpecificSimulatorServiceContext_block_invoke_2 + 162
    6   IDEInterfaceBuilderCocoaTouchIntegration 0x00000001199bf20e __IBSharedInterfaceBuilderSpecificSimulatorServiceContext_block_invoke + 28
    7   libdispatch.dylib                   0x00007fff5e523db8 _dispatch_client_callout + 8
    8   libdispatch.dylib                   0x00007fff5e523d6b dispatch_once_f + 41
    9   IDEInterfaceBuilderCocoaTouchIntegration 0x00000001199bf1ad IBSharedInterfaceBuilderSpecificSimulatorServiceContext + 1165
    10  IDEInterfaceBuilderCocoaTouchIntegration 0x000000011989d03e -[IBCocoaTouchIdiom trySimDeviceTypeForIdentifier:error:] + 56
    11  IDEInterfaceBuilderCocoaTouchIntegration 0x000000011989d1f9 -[IBCocoaTouchIdiom simDeviceTypeForToolDescription:error:] + 153
    12  IDEInterfaceBuilderCocoaTouchIntegration 0x0000000119956ea4 -[IBCocoaTouchPlatformToolDescription preferredDeviceTypeReturningError:] + 114
    13  IDEInterfaceBuilderCocoaTouchIntegration 0x00000001198722f7 -[IBCocoaTouchToolManager executionContextForDescription:error:] + 225
    14  IDEInterfaceBuilderKit              0x000000010ab07e41 -[IBAbstractInterfaceBuilderPlatformToolManager _determineContextsForLaunchingToolWithDescription:returningLaunchContext:returningExecutionContext:returningFailureContext:error:forReason:] + 136
    15  IDEInterfaceBuilderKit              0x000000010ab0815f -[IBAbstractInterfaceBuilderPlatformToolManager launchNewToolWithDescription:error:forReason:] + 154
    16  IDEInterfaceBuilderCocoaTouchIntegration 0x0000000119872e04 -[IBCocoaTouchToolManager launchNewToolWithDescription:error:forReason:] + 89
    17  IDEInterfaceBuilderKit              0x000000010ab05d66 -[IBAbstractInterfaceBuilderPlatformToolManager cachedToolIncrementBusyWithDescription:error:forReason:] + 258
    18  IDEInterfaceBuilderCocoaTouchIntegration 0x0000000119872ca0 -[IBCocoaTouchToolManager cachedToolIncrementBusyWithDescription:error:forReason:] + 89
    19  IDEInterfaceBuilderCocoaTouchIntegration 0x00000001198f04ce __122-[IBCocoaTouchXIBDocumentCompiler compiledKeyedObjectsDataWithMarshallingContext:archivingContext:diagnosticsBlock:error:]_block_invoke.95 + 267
    20  libdispatch.dylib                   0x00007fff5e523db8 _dispatch_client_callout + 8
    21  libdispatch.dylib                   0x00007fff5e5371e1 _dispatch_queue_barrier_sync_invoke_and_complete + 60
    22  DVTFoundation                       0x000000010b7613db DVTDispatchSync + 208
    23  IDEInterfaceBuilderCocoaTouchIntegration 0x00000001198efe26 -[IBCocoaTouchXIBDocumentCompiler compiledKeyedObjectsDataWithMarshallingContext:archivingContext:diagnosticsBlock:error:] + 3436
    24  IDEInterfaceBuilderCocoaTouchIntegration 0x00000001198f163c __121-[IBCocoaTouchXIBDocumentCompiler compiledPackageWithOptions:marshallingContext:archivingContext:diagnosticsBlock:error:]_block_invoke + 72
    25  IDEInterfaceBuilderKit              0x000000010abada43 __85-[IBDocumentCompiler invokeWithIntermediateDocumentOfTargetRuntime:alwaysCopy:block:]_block_invoke + 137
    26  IDEInterfaceBuilderKit              0x000000010abad7b2 -[IBDocumentCompiler invokeWithIntermediateDocument:] + 244
    27  IDEInterfaceBuilderKit              0x000000010abad970 -[IBDocumentCompiler invokeWithIntermediateDocumentOfTargetRuntime:alwaysCopy:block:] + 244
    28  IDEInterfaceBuilderCocoaTouchIntegration 0x00000001198f0c56 -[IBCocoaTouchXIBDocumentCompiler compiledPackageWithOptions:marshallingContext:archivingContext:diagnosticsBlock:error:] + 696
    29  IDEInterfaceBuilderCocoaTouchIntegration 0x00000001198f195b -[IBCocoaTouchXIBDocumentCompiler compileWithOptions:error:] + 380
    30  IDEInterfaceBuilderKit              0x000000010abadb4a +[IBDocumentCompiler compileContentsOfDocument:options:error:] + 123
    31  IDEInterfaceBuilderKit              0x000000010ab67076 __47-[IBDocument compiledPackageWithOptions:error:]_block_invoke + 56
    32  IDEInterfaceBuilderKit              0x000000010abab2b9 -[IBDocumentAutolayoutManager ignoreAutolayoutStatusInvalidationDuring:] + 27
    33  IDEInterfaceBuilderKit              0x000000010ab66fca -[IBDocument compiledPackageWithOptions:error:] + 227
    34  IDEInterfaceBuilderKit              0x000000010ab67315 -[IBDocument compileAndWriteToPath:withOptions:error:] + 180
    35  ibtoold                             0x000000010a9c4e73 IBCompileDocumentForSingleTargetDevice + 211
    36  ibtoold                             0x000000010a9c073c -[IBCLIInterfaceBuilderToolPersona invokeArguments:outputDictionary:] + 26169
    37  ibtoold                             0x000000010a9c367e -[IBCLIInterfaceBuilderToolPersona runSingleInvocation:outputtingToFileHandle:andVerifyingEnvironment:] + 3171
    38  ibtoold                             0x000000010a9c70e7 IBCLIServerRunSingleInvocation + 520
    39  ibtoold                             0x000000010a9c773e __IBCLIServerRunSingleInvocationWithIODirectedAtPipesAndUnlinkOnSuccess_block_invoke_2 + 34
    40  ibtoold                             0x000000010a9c760c __IBCLIServerRunSingleInvocationWithIODirectedAtPipesAndUnlinkOnSuccess_block_invoke + 857
    41  ibtoold                             0x000000010a9b63f5 -[IBCLIErrorForwarder forwardErrorOutputToDescriptor:whileInvokingBlock:] + 110
    42  ibtoold                             0x000000010a9c6c9d IBCLIServerRunSingleInvocationWithIODirectedAtPipesAndUnlinkOnSuccess + 581
    43  ibtoold                             0x000000010a9c5a7d main + 2673
    44  libdyld.dylib                       0x00007fff5e55d015 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException (PrismSample2.iOS)