diff --git a/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj b/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj
index a74b2f3a44..8e60a55100 100644
--- a/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj
+++ b/OpenRA.Mods.RA/OpenRA.Mods.RA.csproj
@@ -37,6 +37,10 @@
     <OutputPath>bin\Release\</OutputPath>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="ICSharpCode.SharpZipLib, Version=0.86.0.518, Culture=neutral, PublicKeyToken=1b03e6acf1164f73, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\ICSharpCode.SharpZipLib.dll</HintPath>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>