diff --git a/releases/net471/KnownIssues/553390 - BCL - SGEN crashes because it references System.IO.Compression.ZipFile.dll.md b/releases/net471/KnownIssues/553390 - BCL - SGEN crashes because it references System.IO.Compression.ZipFile.dll.md
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+# SGEN crashes trying to load the System.IO.Compression.FileSystem reference assembly
+
+## Symptoms
+
+When building an application that uses the [XML Serializer Generator Tool (SGen.exe)](https://docs.microsoft.com/en-us/dotnet/standard/serialization/xml-serializer-generator-tool-sgen-exe), you get an error similar to this one:
+
+```
+An attempt was made to load an assembly with an incorrect format: C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.7.1\Facades\System.IO.Compression.ZipFile.dll. 
+```
+
+## Cause
+
+.NET Framework 4.7.1 includes a few new assemblies in order to support .NET Standard 2.0. 
+For those assemblies, we added entries in a .NET Framework unification table to ensure that assemblies with different versions will correctly unify to a single one. 
+For the `System.IO.Compression.FileSystem` the information captured in the unification table is incorrect. 
+
+This causes the assembly to not be correctly unified by the .NET Framework and in turn causes SGEN to give out that error.
+
+## Impact
+
+This problem occurs when building the applications that use the SGEN tool.
+
+## Workaround
+
+Add the following targets to the project that is experiencing this issue. 
+The targets remove the reference assemblies from the ReferencePath set that SGEN uses before the serialization assemblies are produced and adds them back after they are produced.
+
+```xml
+<Target Name="RemoveDesignTimeFacadesBeforeSGen" BeforeTargets="GenerateSerializationAssemblies">
+  <ItemGroup>
+    <DesignFacadesToFilter Include="System.IO.Compression.ZipFile" />
+    <_FilterOutFromReferencePath Include="@(_DesignTimeFacadeAssemblies_Names->'%(OriginalIdentity)')" 
+        Condition="'@(DesignFacadesToFilter)' == '@(_DesignTimeFacadeAssemblies_Names)' and '%(Identity)' != ''" /> 
+    <ReferencePath Remove="@(_FilterOutFromReferencePath)" />
+  </ItemGroup>
+  <Message Importance="normal" Text="Removing DesignTimeFacades from ReferencePath before running SGen." /> </Target>
+ 
+<Target Name="ReAddDesignTimeFacadesBeforeSGen" AfterTargets="GenerateSerializationAssemblies">
+  <ItemGroup>
+    <ReferencePath Include="@(_FilterOutFromReferencePath)" />
+  </ItemGroup>
+  <Message Importance="normal" Text="Adding back DesignTimeFacades from ReferencePath now that SGen has ran." />
+</Target>
+```
+
+## Resolution
+
+This problem is fixed in [.NET Framework 4.7.2](http://go.microsoft.com/fwlink/?LinkId=863281).