diff --git a/OpenRA.Mods.Common/Installer/InstallerUtils.cs b/OpenRA.Mods.Common/Installer/InstallerUtils.cs
index d0b4144a75..0f0f71a42e 100644
--- a/OpenRA.Mods.Common/Installer/InstallerUtils.cs
+++ b/OpenRA.Mods.Common/Installer/InstallerUtils.cs
@@ -20,6 +20,9 @@ namespace OpenRA.Mods.Common.Installer
 	{
 		public static bool IsValidSourcePath(string path, ModContent.ModSource source)
 		{
+			if (source.IDFiles == null)
+				return true;
+
 			try
 			{
 				foreach (var kv in source.IDFiles.Nodes)