Cannot recompile UE4

Windows crashed when compiling my (simple) game project and now even the Engine cannot recompile.
Everything was working fine before the crash (previous game compiles ran fine).
Error below. Any help?

1>------ Build started: Project: UE4, Configuration: Development_Editor x64 ------
1>EXEC : error : System.Runtime.Serialization.SerializationException: Binary stream ‘0’ does not contain a valid BinaryHeader. Possible causes are invalid stream or object version change between serialization and deserialization.
1> at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()
1> at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
1> at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
1> at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, IMethodCallMessage methodCallMessage)
1> at UnrealBuildTool.ActionHistory…ctor(String InFilePath) in f:\Github\UnrealEngine-4.2\Engine\Source\Programs\UnrealBuildTool\System\ActionHistory.cs:line 34
1> at UnrealBuildTool.UnrealBuildTool.GetActionsToExecute(List1 OutputItems, List1 Targets) in f:\Github\UnrealEngine-4.2\Engine\Source\Programs\UnrealBuildTool\System\ActionGraph.cs:line 183
1> at UnrealBuildTool.UnrealBuildTool.RunUBT(String] Arguments) in f:\Github\UnrealEngine-4.2\Engine\Source\Programs\UnrealBuildTool\System\UnrealBuildTool.cs:line 1152
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V120\Microsoft.MakeFile.Targets(38,5): error MSB3073: The command “…..\Build\BatchFiles\Build.bat UE4Editor Win64 Development” exited with code -1.
========== Build: 0 succeeded, 1 failed, 1 up-to-date, 0 skipped ==========

Fixed.
If it happens to you, delete Engine\Intermediate\Build\ActionHistory.bin and the engine will recompile fine.