diff --git a/UIXC/Commands/DecompileCommand.cs b/UIXC/Commands/DecompileCommand.cs
index c23bf94..a7a0818 100644
--- a/UIXC/Commands/DecompileCommand.cs
+++ b/UIXC/Commands/DecompileCommand.cs
@@ -65,7 +65,7 @@ public class DecompileCommand : CompilerCommandBase<DecompileCommand.Settings>
                     if (uibLoadResult.Status != LoadResultStatus.Success)
                         throw new Exception($"Failed to load UIB source ({uibLoadResult.ErrorContextUri})");
 
-                    var disassembler = Disassembler.Load(uibLoadResult as MarkupLoadResult);
+                    var disassembler = Disassembler.Load(uibLoadResult);
                     var asm = disassembler.Write();
 
                     File.WriteAllText(GetOutputPath(settings, input), asm);
diff --git a/libs/UIX.Asm/Disassembler.cs b/libs/UIX.Asm/Disassembler.cs
index 5f21285..632458b 100644
--- a/libs/UIX.Asm/Disassembler.cs
+++ b/libs/UIX.Asm/Disassembler.cs
@@ -5,7 +5,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.InteropServices;
-using System.Xml.Linq;
 
 namespace Microsoft.Iris.Asm;
 
@@ -26,7 +25,13 @@ public class Disassembler
         };
     }
 
-    public static Disassembler Load(MarkupLoadResult loadResult) => new(loadResult);
+    public static Disassembler Load(LoadResult loadResult)
+    {
+        if (loadResult is not MarkupLoadResult markupLoadResult)
+            throw new ArgumentException($"Disassembly can only be performed on markup. Expected '{nameof(MarkupLoadResult)}', got '{loadResult?.GetType().Name}'.");
+        
+        return new(markupLoadResult);
+    }
 
     public IEnumerable<Directive> GetExports()
     {
diff --git a/libs/UIX.Test/Assembly.cs b/libs/UIX.Test/Assembly.cs
index 625a5b2..b26f331 100644
--- a/libs/UIX.Test/Assembly.cs
+++ b/libs/UIX.Test/Assembly.cs
@@ -97,7 +97,7 @@ Alt_locl:
 
         // Disassemble the compiled UIX
         var sourceLoadResult = MarkupSystem.ResolveLoadResult($"file://{uibFile.Path}", MarkupSystem.RootIslandId);
-        var disassembly = Disassembler.Load(sourceLoadResult as MarkupLoadResult);
+        var disassembly = Disassembler.Load(sourceLoadResult);
         var disassemblyText = disassembly.Write();
         File.WriteAllText(uixaPath, disassemblyText);
 
@@ -164,7 +164,7 @@ Alt_locl:
 
         // Disassemble the compiled UIX
         var sourceLoadResult = MarkupSystem.ResolveLoadResult($"file://{uixFile.Path}", MarkupSystem.RootIslandId);
-        var disassembly = Disassembler.Load(sourceLoadResult as MarkupLoadResult);
+        var disassembly = Disassembler.Load(sourceLoadResult);
         var disassemblyText = disassembly.Write();
         File.WriteAllText(uixaPath, disassemblyText);
 
@@ -217,7 +217,7 @@ Alt_locl:
         string uri = "file://" + tempFile.Path;
 
         var sourceLoadResult = MarkupSystem.ResolveLoadResult(uri, MarkupSystem.RootIslandId);
-        var dis = Disassembler.Load(sourceLoadResult as MarkupLoadResult);
+        var dis = Disassembler.Load(sourceLoadResult);
 
         var disText = dis.Write();
         _output.WriteLine(disText);