Asp.net – CS0656: Missing compiler required member 'Microsoft.CSharp.RuntimeBinder.Binder.InvokeMember' When adding IronPDF

I have an old version of Umbraco, 7.4.5 running on net framework 4.8. When adding IronPDF and trying to load http://localhost/umbraco the page won’t load (run-time error) because presumably, it is trying to reference Microsoft.CSharp from IronPDF via something dynamic in the umbraco backend/razor views/etc.

I’ve tried the following:

• Reinstall iron pdf
• Reinstall umbraco
• Remove the Microsoft.CSharp and add via Nuget
• Aliased all the IronPDF references to something besides global

If I remove IronPDF, umbraco works as expected.

How can I work around this issue?

Microsoft (R) Visual C# Compiler version 4.8.9032.0

for C# 5
Copyright (C) Microsoft Corporation. All rights reserved.



This compiler is provided as part of the Microsoft (R) .NET Framework, but only supports language versions up to C# 5, which is no longer the latest version. For compilers that support newer versions of the C# programming language, see http://go.microsoft.com/fwlink/?LinkID=533240

warning CS1685: The predefined type 'Microsoft.CSharp.RuntimeBinder.Binder' is defined in multiple assemblies in the global alias; using definition from 'c:UsersuserAppDataLocalTempTemporary ASP.NET Filesvsd92acae1c833fd19assemblydl38f945f7d0a6d0bb_f2e5d901IronPdf.DLL'
warning CS1685: The predefined type 'Microsoft.CSharp.RuntimeBinder.CSharpBinderFlags' is defined in multiple assemblies in the global alias; using definition from 'c:UsersuserAppDataLocalTempTemporary ASP.NET Filesvsd92acae1c833fd19assemblydl38f945f7d0a6d0bb_f2e5d901IronPdf.DLL'
warning CS1685: The predefined type 'Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo' is defined in multiple assemblies in the global alias; using definition from 'c:UsersuserAppDataLocalTempTemporary ASP.NET Filesvsd92acae1c833fd19assemblydl38f945f7d0a6d0bb_f2e5d901IronPdf.DLL'
warning CS1685: The predefined type 'Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfoFlags' is defined in multiple assemblies in the global alias; using definition from 'c:UsersuserAppDataLocalTempTemporary ASP.NET Filesvsd92acae1c833fd19assemblydl38f945f7d0a6d0bb_f2e5d901IronPdf.DLL'
warning CS1685: The predefined type 'System.ObsoleteAttribute' is defined in multiple assemblies in the global alias; using definition from 'c:WindowsMicrosoft.NETFramework64v4.0.30319mscorlib.dll'
error CS0656: Missing compiler required member 'Microsoft.CSharp.RuntimeBinder.Binder.InvokeMember'
c:projectsgitwebumbracoViewsDefault.cshtml(71,105): error CS1969: One or more types required to compile a dynamic expression cannot be found. Are you missing a reference?
c:projectsgitwebumbracoViewsDefault.cshtml(76,76): error CS1969: One or more types required to compile a dynamic expression cannot be found. Are you missing a reference?