I received the following message when deploying after updating my version of Xamarin
Severity Code Description Project File Line Suppression State Error Failed to resolve assembly: 'Xamarin.iOS, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065' at Mono.Cecil.BaseAssemblyResolver.Resolve(AssemblyNameReference name, ReaderParameters parameters) at Mono.Cecil.DefaultAssemblyResolver.Resolve(AssemblyNameReference name) at Mono.Cecil.MetadataResolver.Resolve(TypeReference type) at Mono.Cecil.TypeReference.Resolve() at Mono.Cecil.Mixin.CheckedResolve(TypeReference self) at Mono.Cecil.SignatureReader.ReadCustomAttributeEnum(TypeReference enum_type) at Mono.Cecil.SignatureReader.ReadCustomAttributeElementValue(TypeReference type) at Mono.Cecil.SignatureReader.ReadCustomAttributeElement(TypeReference type) at Mono.Cecil.SignatureReader.ReadCustomAttributeFixedArgument(TypeReference type) at Mono.Cecil.SignatureReader.ReadCustomAttributeConstructorArguments(CustomAttribute attribute, Collection`1 parameters) at Mono.Cecil.MetadataReader.ReadCustomAttributeSignature(CustomAttribute attribute) at Mono.Cecil.CustomAttribute.<Resolve>b__2(CustomAttribute attribute, MetadataReader reader) at Mono.Cecil.ModuleDefinition.Read[TItem,TRet](TItem item, Func`3 read) at Mono.Cecil.CustomAttribute.Resolve() at Mono.Cecil.CustomAttribute.get_ConstructorArguments() at Mono.Cecil.ImmediateModuleReader.ReadCustomAttributes(ICustomAttributeProvider provider) at Mono.Cecil.ImmediateModuleReader.ReadMethods(TypeDefinition type) at Mono.Cecil.ImmediateModuleReader.ReadType(TypeDefinition type) at Mono.Cecil.ImmediateModuleReader.ReadTypes(Collection`1 types) at Mono.Cecil.ImmediateModuleReader.ReadModule(ModuleDefinition module) at Mono.Cecil.ModuleWriter.WriteModuleTo(ModuleDefinition module, Stream stream, WriterParameters parameters) at Mono.Cecil.ModuleDefinition.Write(Stream stream, WriterParameters parameters) at Mono.Cecil.ModuleDefinition.Write(String fileName, WriterParameters parameters) at Xamarin.Build.Download.XamarinBuildiOSResourceRestore.MergeResources(IAssemblyResolver resolver, String originalAsmPath, String mergedAsmPath, List`1 resourceItems) CanadianClassifiedsAlerter.iOS
After verifying both my build server and development machine were running the same version of Xamarin, I noticed a slight hint at the end of the message
at Xamarin.Build.Download.XamarinBuildiOSResourceRestore
Solution
I fixed it by updating Xamarin.Forms and Xamarin.Build.Download in both my Portable project and the iOS project and it built just fine 🙂
It’s that easy.