Error Occurs when creating new C++ Project

Hello all,

I’m using a MacBook Pro OS version 10.14.1, Xcode 10.1, and Unreal Engine 4.21.

Every time I try to create a new C++ Project (Basic Code), I get the following error and I can’t figure out how to fix it. Does anyone have experience with this error?

An error occurred while trying to generate project files.


Running Mono...

Found mono via known Mono.framework path
Running installed mono, version:  Mono JIT compiler version 5.12.0.301 (2018-02/4fe3280bba1 Fri Jul 20 08:25:42 EDT 2018)
/Users/Shared/Epic Games/UE_4.21/Engine /Users/Shared/Epic Games/UE_4.21/Engine/Binaries/Mac
Discovering modules, targets and source code for project...
Generating data for project indexing...
Generating data for project indexing... 100%
Writing project files...
Writing project files... 33%
ERROR: UnrealBuildTool Exception: System.FormatException: Input string was not in a correct format.
         at System.Number.ParseSingle (System.String value, System.Globalization.NumberStyles options, System.Globalization.NumberFormatInfo numfmt) [0x00083] in <f3f2aa82c3a04d48845485ce37124803>:0 
         at System.Single.Parse (System.String s, System.Globalization.NumberStyles style, System.Globalization.NumberFormatInfo info) [0x00000] in <f3f2aa82c3a04d48845485ce37124803>:0 
         at System.Single.Parse (System.String s) [0x0000b] in <f3f2aa82c3a04d48845485ce37124803>:0 
         at UnrealBuildTool.IOSExports.SupportsIconCatalog (Tools.DotNETCommon.DirectoryReference ProjectDirectory, Tools.DotNETCommon.FileReference BuildRecieptFileName) [0x0005e] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.UEDeployIOS.GenerateIOSPList (Tools.DotNETCommon.FileReference ProjectFile, UnrealBuildTool.UnrealTargetConfiguration Config, System.String ProjectDirectory, System.Boolean bIsUE4Game, System.String GameName, System.String ProjectName, System.String InEngineDir, System.String AppDirectory, Tools.DotNETCommon.FileReference BuildRecieptFileName, System.Boolean& bSupportsPortrait, System.Boolean& bSupportsLandscape, System.Boolean& bSkipIcons, UnrealBuildTool.UEDeployIOS InThis) [0x00a4f] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.XcodeProjectFile.AppendNativeTargetBuildConfiguration (System.Text.StringBuilder Content, UnrealBuildTool.XcodeProjectFile+XcodeBuildConfig Config, System.String ConfigGuid, System.Boolean bIsAGame, Tools.DotNETCommon.FileReference ProjectFile) [0x00b87] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.XcodeProjectFile.AppendXCBuildConfigurationSection (System.Text.StringBuilder Content, System.Collections.Generic.Dictionary`2[TKey,TValue] ProjectBuildConfigs, System.Collections.Generic.Dictionary`2[TKey,TValue] TargetBuildConfigs, System.Collections.Generic.Dictionary`2[TKey,TValue] BuildTargetBuildConfigs, System.Collections.Generic.Dictionary`2[TKey,TValue] IndexTargetBuildConfigs, System.Boolean bIsAGame, Tools.DotNETCommon.FileReference GameProjectPath) [0x00083] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.XcodeProjectFile.WriteProjectFile (System.Collections.Generic.List`1[T] InPlatforms, System.Collections.Generic.List`1[T] InConfigurations) [0x0033c] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.ProjectFileGenerator.WriteProjectFiles () [0x0002e] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.ProjectFileGenerator.GenerateProjectFiles (System.String[] Arguments) [0x00caa] in <ce6fb750202f418399b0d4c7f927cc99>:0 
         at UnrealBuildTool.UnrealBuildTool.GuardedMain (System.String[] Arguments) [0x00f54] in <ce6fb750202f418399b0d4c7f927cc99>:0

Found a similar question with a possible solution: https://answers.unrealengine.com/questions/839152/input-string-was-not-in-a-correct-format-ios-packa.html#

I have the same system configuration (except for a slightly newer Mono JIT compiler) and the same error. Resetting the Xcode paths as in the suggested link did not resolve the problem, unfortunately. Perhaps Xcode 10.1 is not supported yet.

Problem solved by changing language to English on macOS: [4.18.1] Iphone launch / packaging fails with System.FormatException: Unknown char at at UnrealBuildTool.IOSExports.SupportsIconCatalog - Programming & Scripting - Epic Developer Community Forums

im pretty sure xcode 10 does work but if changing the language as told by Greg Olsson doesnt work try downgrading to xcode 9.4.

It looks like it has to do with what is used to indicate decimal points (period or a comma). My primary language is set to Polish, and Europe uses the comma as a decimal point, which must have been messing with some paths. You don’t necessarily need to change the language to English, just go into advanced settings for the language and change what is used for the decimal point.