diff --git a/Wabbajack.Lib/Downloaders/GameFileSourceDownloader.cs b/Wabbajack.Lib/Downloaders/GameFileSourceDownloader.cs
index 2cdf66d4..28f29ccc 100644
--- a/Wabbajack.Lib/Downloaders/GameFileSourceDownloader.cs
+++ b/Wabbajack.Lib/Downloaders/GameFileSourceDownloader.cs
@@ -62,7 +62,7 @@ namespace Wabbajack.Lib.Downloaders
             internal AbsolutePath SourcePath => Game.MetaData().GameLocation().Combine(GameFile);
 
             [JsonIgnore]
-            public override object[] PrimaryKey { get => new object[] {Game, GameVersion, GameFile}; }
+            public override object[] PrimaryKey { get => new object[] {Game, GameVersion ?? "0.0.0.0", GameFile}; }
 
             public override bool IsWhitelisted(ServerWhitelist whitelist)
             {