diff --git a/src/Riok.Mapperly/Descriptors/MappingBuilders/ExplicitCastMappingBuilder.cs b/src/Riok.Mapperly/Descriptors/MappingBuilders/ExplicitCastMappingBuilder.cs
index 587414bddd..756479c60d 100644
--- a/src/Riok.Mapperly/Descriptors/MappingBuilders/ExplicitCastMappingBuilder.cs
+++ b/src/Riok.Mapperly/Descriptors/MappingBuilders/ExplicitCastMappingBuilder.cs
@@ -1,3 +1,4 @@
+using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Riok.Mapperly.Abstractions;
 using Riok.Mapperly.Descriptors.Mappings;
@@ -15,6 +16,9 @@ public static class ExplicitCastMappingBuilder
         if (ctx.MapperConfiguration.UseDeepCloning && !ctx.Source.IsImmutable() && !ctx.Target.IsImmutable())
             return null;
 
+        if (SymbolEqualityComparer.Default.Equals(ctx.Source, ctx.Compilation.ObjectType))
+            return null;
+
         var conversion = ctx.Compilation.ClassifyConversion(ctx.Source, ctx.Target);
 
         // only allow user defined explicit reference conversions
diff --git a/test/Riok.Mapperly.Tests/Mapping/CastTest.cs b/test/Riok.Mapperly.Tests/Mapping/CastTest.cs
index 4121a26134..56365f8c44 100644
--- a/test/Riok.Mapperly.Tests/Mapping/CastTest.cs
+++ b/test/Riok.Mapperly.Tests/Mapping/CastTest.cs
@@ -363,4 +363,14 @@ public void ExplicitCastMappingDisabledShouldDiagnostic()
             .Should()
             .HaveDiagnostic(new(DiagnosticDescriptors.CouldNotCreateMapping));
     }
+
+    [Fact]
+    public void FromObjectExplicitCastShouldBeIgnoredAndDiagnostic()
+    {
+        var source = TestSourceBuilder.Mapping("object", "byte");
+        TestHelper
+            .GenerateMapper(source, TestHelperOptions.AllowDiagnostics)
+            .Should()
+            .HaveDiagnostic(new(DiagnosticDescriptors.CouldNotCreateMapping));
+    }
 }