diff --git a/CHANGELOG.md b/CHANGELOG.md
index fc374025e0..ecffca69f4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,9 @@
 # Changelog
 All changes to the project will be documented in this file.
 
+## [1.35.1] - not yet released
+* Fixed not supported exception when trying to decompile a BCL assembly on Mono (PR: [#1767](https://github.com/OmniSharp/omnisharp-roslyn/pull/1767))
+
 ## [1.35.0] - 2020-04-10
 * Support for `<RunAnalyzers />` and `<RunAnalyzersDuringLiveAnalysis />` (PR: [#1739](https://github.com/OmniSharp/omnisharp-roslyn/pull/1739))
 * Add `typeparam` documentation comments to text description ([omnisharp-vscode#3516](https://github.com/OmniSharp/omnisharp-vscode/issues/3516), PR: [#1749](https://github.com/OmniSharp/omnisharp-roslyn/pull/1749))
diff --git a/src/OmniSharp.Roslyn.CSharp/OmniSharp.Roslyn.CSharp.csproj b/src/OmniSharp.Roslyn.CSharp/OmniSharp.Roslyn.CSharp.csproj
index 80997f7afb..2f38e3b5ce 100644
--- a/src/OmniSharp.Roslyn.CSharp/OmniSharp.Roslyn.CSharp.csproj
+++ b/src/OmniSharp.Roslyn.CSharp/OmniSharp.Roslyn.CSharp.csproj
@@ -18,7 +18,6 @@
         <PackageReference Include="System.Reactive" />
         <PackageReference Include="ICSharpCode.Decompiler" />
         <PackageReference Include="Microsoft.CodeAnalysis.CSharp" />
-        <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" />
         <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Features" />
         <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" />
         <PackageReference Include="Microsoft.VisualStudio.CodingConventions" />
diff --git a/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/DecompilationExternalSourceService.cs b/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/DecompilationExternalSourceService.cs
index cc99c3d2e5..33784aa0e0 100644
--- a/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/DecompilationExternalSourceService.cs
+++ b/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/DecompilationExternalSourceService.cs
@@ -26,10 +26,10 @@ public class DecompilationExternalSourceService : BaseExternalSourceService, IEx
         private readonly Lazy<OmniSharpCSharpDecompiledSourceService> _service;
 
         [ImportingConstructor]
-        public DecompilationExternalSourceService(IAssemblyLoader loader, ILoggerFactory loggerFactory, OmniSharpWorkspace omniSharpWorkspace) : base(loader)
+        public DecompilationExternalSourceService(IAssemblyLoader loader, ILoggerFactory loggerFactory) : base(loader)
         {
             _loggerFactory = loggerFactory;
-            _service = new Lazy<OmniSharpCSharpDecompiledSourceService>(() => new OmniSharpCSharpDecompiledSourceService(omniSharpWorkspace.Services.GetLanguageServices(LanguageNames.CSharp), _loader, _loggerFactory));
+            _service = new Lazy<OmniSharpCSharpDecompiledSourceService>(() => new OmniSharpCSharpDecompiledSourceService(_loader, _loggerFactory));
         }
 
         public async Task<(Document document, string documentPath)> GetAndAddExternalSymbolDocument(Project project, ISymbol symbol, CancellationToken cancellationToken)
diff --git a/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/OmniSharpCSharpDecompiledSourceService.cs b/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/OmniSharpCSharpDecompiledSourceService.cs
index 5fd684c1b7..d4a4058ebf 100644
--- a/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/OmniSharpCSharpDecompiledSourceService.cs
+++ b/src/OmniSharp.Roslyn.CSharp/Services/Decompilation/OmniSharpCSharpDecompiledSourceService.cs
@@ -23,7 +23,6 @@
 using OmniSharp.Extensions;
 using System.IO;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Scripting;
 using OmniSharp.Services;
 using System.Reflection;
 using OmniSharp.Utilities;
@@ -34,7 +33,6 @@ namespace OmniSharp.Roslyn.CSharp.Services.Decompilation
 {
     public class OmniSharpCSharpDecompiledSourceService
     {
-        private readonly HostLanguageServices _provider;
         private readonly ILoggerFactory _loggerFactory;
         private const string MetadataAsSourceHelpers = "Microsoft.CodeAnalysis.MetadataAsSource.MetadataAsSourceHelpers";
         private const string CSharpDocumentationCommentFormattingService = "Microsoft.CodeAnalysis.CSharp.DocumentationComments.CSharpDocumentationCommentFormattingService";
@@ -48,7 +46,7 @@ public class OmniSharpCSharpDecompiledSourceService
         private readonly Lazy<MethodInfo> _metadataGetAssemblyInfo;
         private readonly Lazy<MethodInfo> _metadataGetAssemblyDisplay;
 
-        public OmniSharpCSharpDecompiledSourceService(HostLanguageServices provider, IAssemblyLoader loader, ILoggerFactory loggerFactory)
+        public OmniSharpCSharpDecompiledSourceService(IAssemblyLoader loader, ILoggerFactory loggerFactory)
         {
             _roslynFeatureAssembly = loader.LazyLoad(Configuration.RoslynFeatures);
             _csharpFeatureAssembly = loader.LazyLoad(Configuration.RoslynCSharpFeatures);
@@ -58,7 +56,6 @@ public OmniSharpCSharpDecompiledSourceService(HostLanguageServices provider, IAs
             _metadataGetAssemblyInfo = _csharpMetadataAsSourceService.LazyGetMethod("GetAssemblyInfo");
             _metadataGetAssemblyDisplay = _csharpMetadataAsSourceService.LazyGetMethod("GetAssemblyDisplay");
 
-            _provider = provider;
             _loggerFactory = loggerFactory;
         }
 
@@ -68,36 +65,11 @@ public async Task<Document> AddSourceToAsync(Document document, Compilation symb
             var containingOrThis = symbol.GetContainingTypeOrThis();
             var fullName = GetFullReflectionName(containingOrThis);
 
-            string assemblyLocation = null;
-            var isReferenceAssembly = symbol.ContainingAssembly.GetAttributes().Any(attribute => attribute.AttributeClass.Name == nameof(ReferenceAssemblyAttribute)
-                && attribute.AttributeClass.ToNameDisplayString() == typeof(ReferenceAssemblyAttribute).FullName);
-            if (isReferenceAssembly)
-            {
-                try
-                {
-                    var fullAssemblyName = symbol.ContainingAssembly.Identity.GetDisplayName();
-
-                    var globalAssemblyCacheType = typeof(ScriptOptions).Assembly.GetType("Microsoft.CodeAnalysis.GlobalAssemblyCache");
-                    var instance = globalAssemblyCacheType.GetField("Instance", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null);
-
-                    var args = new object[] { fullAssemblyName, assemblyLocation, null, CultureInfo.CurrentCulture };
-                    instance.GetType().InvokeMember("ResolvePartialName", BindingFlags.InvokeMethod, Type.DefaultBinder, instance, args);
-                    assemblyLocation = (string)args[1];
-                }
-                catch (Exception)
-                {
-                    // log
-                }
-            }
-
+            var reference = symbolCompilation.GetMetadataReference(symbol.ContainingAssembly);
+            var assemblyLocation = (reference as PortableExecutableReference)?.FilePath;
             if (assemblyLocation == null)
             {
-                var reference = symbolCompilation.GetMetadataReference(symbol.ContainingAssembly);
-                assemblyLocation = (reference as PortableExecutableReference)?.FilePath;
-                if (assemblyLocation == null)
-                {
-                    throw new NotSupportedException("Cannot_navigate_to_the_symbol_under_the_caret");
-                }
+                throw new NotSupportedException("Cannot_navigate_to_the_symbol_under_the_caret");
             }
 
             // Decompile