diff --git a/YAFCparser/FactorioDataSource.cs b/YAFCparser/FactorioDataSource.cs
index 87c97072..2442292d 100644
--- a/YAFCparser/FactorioDataSource.cs
+++ b/YAFCparser/FactorioDataSource.cs
@@ -63,7 +63,8 @@ public static bool ModPathExists(string modName, string path)
 
         public static byte[] ReadModFile(string modName, string path)
         {
-            var info = allMods[modName];
+            if (!allMods.TryGetValue(modName, out var info))
+                return null;
             if (info.zipArchive != null)
             {
                 var entry = info.zipArchive.GetEntry(info.folder + path);