diff --git a/OpenRA.Game/GameRules/RulesetCache.cs b/OpenRA.Game/GameRules/RulesetCache.cs
index 715ea41f63..f61320f845 100644
--- a/OpenRA.Game/GameRules/RulesetCache.cs
+++ b/OpenRA.Game/GameRules/RulesetCache.cs
@@ -122,7 +122,8 @@ namespace OpenRA
 			return itemSet;
 		}
 
-		Dictionary<string, TileSet> LoadTileSets(IReadOnlyFileSystem fileSystem, Dictionary<string, TileSet> itemCache, Dictionary<string, SequenceCache> sequenceCaches, string[] files)
+		Dictionary<string, TileSet> LoadTileSets(IReadOnlyFileSystem fileSystem, Dictionary<string, TileSet> itemCache,
+			Dictionary<string, SequenceCache> sequenceCaches, string[] files)
 		{
 			var items = new Dictionary<string, TileSet>();
 
@@ -133,7 +134,7 @@ namespace OpenRA
 					items.Add(t.Id, t);
 				else
 				{
-					t = new TileSet(modData, file);
+					t = new TileSet(fileSystem, file);
 					itemCache.Add(file, t);
 
 					// every time we load a tile set, we create a sequence cache for it
diff --git a/OpenRA.Game/Map/TileSet.cs b/OpenRA.Game/Map/TileSet.cs
index 67e0ca3927..903dea1569 100644
--- a/OpenRA.Game/Map/TileSet.cs
+++ b/OpenRA.Game/Map/TileSet.cs
@@ -12,6 +12,7 @@ using System.Collections.Generic;
 using System.Drawing;
 using System.IO;
 using System.Linq;
+using OpenRA.FileSystem;
 using OpenRA.Primitives;
 
 namespace OpenRA
@@ -191,9 +192,9 @@ namespace OpenRA
 		// Private default ctor for serialization comparison
 		TileSet() { }
 
-		public TileSet(ModData modData, string filepath)
+		public TileSet(IReadOnlyFileSystem fileSystem, string filepath)
 		{
-			var yaml = MiniYaml.DictFromStream(modData.ModFiles.Open(filepath));
+			var yaml = MiniYaml.DictFromStream(fileSystem.Open(filepath));
 
 			// General info
 			FieldLoader.Load(this, yaml["General"]);
diff --git a/OpenRA.Mods.Cnc/ImportTiberianDawnLegacyMapCommand.cs b/OpenRA.Mods.Cnc/ImportTiberianDawnLegacyMapCommand.cs
index 818b3f8b93..a95ab4fa03 100644
--- a/OpenRA.Mods.Cnc/ImportTiberianDawnLegacyMapCommand.cs
+++ b/OpenRA.Mods.Cnc/ImportTiberianDawnLegacyMapCommand.cs
@@ -142,7 +142,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 
 		public override void ReadPacks(IniFile file, string filename)
 		{
-			using (var s = Game.ModData.ModFiles.Open(filename.Substring(0, filename.Length - 4) + ".bin"))
+			using (var s = ModData.DefaultFileSystem.Open(filename.Substring(0, filename.Length - 4) + ".bin"))
 				UnpackTileData(s);
 
 			ReadOverlay(file);
diff --git a/OpenRA.Mods.Common/UtilityCommands/CheckSequenceSprites.cs b/OpenRA.Mods.Common/UtilityCommands/CheckSequenceSprites.cs
index 32df401ae1..37e4e85a7d 100644
--- a/OpenRA.Mods.Common/UtilityCommands/CheckSequenceSprites.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/CheckSequenceSprites.cs
@@ -32,7 +32,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 
 			foreach (var t in modData.Manifest.TileSets)
 			{
-				var ts = new TileSet(modData, t);
+				var ts = new TileSet(modData.DefaultFileSystem, t);
 				Console.WriteLine("Tileset: " + ts.Name);
 				var sc = new SpriteCache(modData.DefaultFileSystem, modData.SpriteLoaders, new SheetBuilder(SheetType.Indexed));
 				var nodes = MiniYaml.Merge(modData.Manifest.Sequences.Select(s => MiniYaml.FromStream(modData.DefaultFileSystem.Open(s))));
diff --git a/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs b/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs
index cb75142c0f..c7ded37ed9 100644
--- a/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/FixClassicTilesets.cs
@@ -44,7 +44,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 
 			foreach (var t in modData.Manifest.TileSets)
 			{
-				var ts = new TileSet(modData, t);
+				var ts = new TileSet(modData.DefaultFileSystem, t);
 				var frameCache = new FrameCache(modData.DefaultFileSystem, modData.SpriteLoaders);
 
 				Console.WriteLine("Tileset: " + ts.Name);
diff --git a/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs b/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
index 8cb3afbba9..bc21ec4f6a 100644
--- a/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
@@ -29,6 +29,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 			MapSize = mapSize;
 		}
 
+		public ModData ModData;
 		public Map Map;
 		public Ruleset Rules;
 		public List<string> Players = new List<string>();
@@ -42,9 +43,10 @@ namespace OpenRA.Mods.Common.UtilityCommands
 		[Desc("FILENAME", "Convert a legacy INI/MPR map to the OpenRA format.")]
 		public virtual void Run(ModData modData, string[] args)
 		{
+			ModData = modData;
+
 			// HACK: The engine code assumes that Game.modData is set.
 			Game.ModData = modData;
-
 			Rules = modData.RulesetCache.Load(modData.DefaultFileSystem);
 
 			var filename = args[1];
diff --git a/OpenRA.Mods.Common/Widgets/Logic/CreditsLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/CreditsLogic.cs
index a65305d7e2..3c7a985d35 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/CreditsLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/CreditsLogic.cs
@@ -20,6 +20,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		public CreditsLogic(Widget widget, Action onExit)
 		{
 			var panel = widget.Get("CREDITS_PANEL");
+			var modData = Game.ModData;
 
 			panel.Get<ButtonWidget>("BACK_BUTTON").OnClick = () =>
 			{
@@ -31,7 +32,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			var template = scrollPanel.Get<LabelWidget>("CREDITS_TEMPLATE");
 			scrollPanel.RemoveChildren();
 
-			var lines = Game.ModData.ModFiles.Open("AUTHORS").ReadAllLines();
+			var lines = modData.DefaultFileSystem.Open("AUTHORS").ReadAllLines();
 			foreach (var l in lines)
 			{
 				// Improve the formatting
diff --git a/OpenRA.Mods.Common/Widgets/VqaPlayerWidget.cs b/OpenRA.Mods.Common/Widgets/VqaPlayerWidget.cs
index 373a746f41..9b02045006 100644
--- a/OpenRA.Mods.Common/Widgets/VqaPlayerWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/VqaPlayerWidget.cs
@@ -41,7 +41,7 @@ namespace OpenRA.Mods.Common.Widgets
 		{
 			if (filename == cachedVideo)
 				return;
-			var video = new VqaReader(Game.ModData.ModFiles.Open(filename));
+			var video = new VqaReader(Game.ModData.DefaultFileSystem.Open(filename));
 
 			cachedVideo = filename;
 			Open(video);