diff --git a/OpenRA.Mods.Cnc/FileSystem/MixFile.cs b/OpenRA.Mods.Cnc/FileSystem/MixFile.cs
index f9c9c5af7c..afc902d36b 100644
--- a/OpenRA.Mods.Cnc/FileSystem/MixFile.cs
+++ b/OpenRA.Mods.Cnc/FileSystem/MixFile.cs
@@ -32,7 +32,7 @@ namespace OpenRA.Mods.Cnc.FileSystem
 			readonly long dataStart;
 			readonly Stream s;
 
-			public MixFile(Stream s, string filename, HashSet<string> allPossibleFilenames)
+			public MixFile(Stream s, string filename, string[] globalFilenames)
 			{
 				Name = filename;
 				this.s = s;
@@ -55,7 +55,7 @@ namespace OpenRA.Mods.Cnc.FileSystem
 
 					index = ParseIndex(entries.ToDictionaryWithConflictLog(x => x.Hash,
 						$"{filename} ({(isCncMix ? "C&C" : "RA/TS/RA2")} format, Encrypted: {isEncrypted}, DataStart: {dataStart})",
-						null, x => $"(offs={x.Offset}, len={x.Length})"), allPossibleFilenames);
+						null, x => $"(offs={x.Offset}, len={x.Length})"), globalFilenames);
 				}
 				catch (Exception)
 				{
@@ -64,10 +64,11 @@ namespace OpenRA.Mods.Cnc.FileSystem
 				}
 			}
 
-			Dictionary<string, PackageEntry> ParseIndex(Dictionary<uint, PackageEntry> entries, HashSet<string> allPossibleFilenames)
+			Dictionary<string, PackageEntry> ParseIndex(Dictionary<uint, PackageEntry> entries, string[] globalFilenames)
 			{
 				var classicIndex = new Dictionary<string, PackageEntry>();
 				var crcIndex = new Dictionary<string, PackageEntry>();
+				IEnumerable<string> allPossibleFilenames = globalFilenames;
 
 				// Try and find a local mix database
 				var dbNameClassic = PackageEntry.HashFilename("local mix database.dat", PackageHashType.Classic);
@@ -79,15 +80,14 @@ namespace OpenRA.Mods.Cnc.FileSystem
 						using (var content = GetContent(kv.Value))
 						{
 							var db = new XccLocalDatabase(content);
-							foreach (var e in db.Entries)
-								allPossibleFilenames.Add(e);
+							allPossibleFilenames = allPossibleFilenames.Concat(db.Entries);
 						}
 
 						break;
 					}
 				}
 
-				foreach (var filename in allPossibleFilenames)
+				foreach (var filename in allPossibleFilenames.Distinct())
 				{
 					var classicHash = PackageEntry.HashFilename(filename, PackageHashType.Classic);
 					var crcHash = PackageEntry.HashFilename(filename, PackageHashType.CRC32);
@@ -223,6 +223,8 @@ namespace OpenRA.Mods.Cnc.FileSystem
 			}
 		}
 
+		string[] globalFilenames;
+
 		bool IPackageLoader.TryParsePackage(Stream s, string filename, FS context, out IReadOnlyPackage package)
 		{
 			if (!filename.EndsWith(".mix", StringComparison.InvariantCultureIgnoreCase))
@@ -232,13 +234,12 @@ namespace OpenRA.Mods.Cnc.FileSystem
 			}
 
 			// Load the global mix database
-			var allPossibleFilenames = new HashSet<string>();
-			if (context.TryOpen("global mix database.dat", out var mixDatabase))
-				using (var db = new XccGlobalDatabase(mixDatabase))
-					foreach (var e in db.Entries)
-						allPossibleFilenames.Add(e);
+			if (globalFilenames == null)
+				if (context.TryOpen("global mix database.dat", out var mixDatabase))
+					using (var db = new XccGlobalDatabase(mixDatabase))
+						globalFilenames = db.Entries.Distinct().ToArray();
 
-			package = new MixFile(s, filename, allPossibleFilenames);
+			package = new MixFile(s, filename, globalFilenames ?? Array.Empty<string>());
 			return true;
 		}
 	}
diff --git a/OpenRA.Mods.Cnc/UtilityCommands/ListMixContentsCommand.cs b/OpenRA.Mods.Cnc/UtilityCommands/ListMixContentsCommand.cs
index e06f2ec936..f9f9e741ee 100644
--- a/OpenRA.Mods.Cnc/UtilityCommands/ListMixContentsCommand.cs
+++ b/OpenRA.Mods.Cnc/UtilityCommands/ListMixContentsCommand.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using OpenRA.Mods.Cnc.FileFormats;
@@ -30,12 +29,11 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 		[Desc("ARCHIVE.MIX", "MIXDATABASE.DAT", "Lists the content ranges for a mix file")]
 		void IUtilityCommand.Run(Utility utility, string[] args)
 		{
-			var allPossibleFilenames = new HashSet<string>();
+			string[] globalFilenames;
 			using (var db = new XccGlobalDatabase(File.OpenRead(args[2])))
-				foreach (var e in db.Entries)
-					allPossibleFilenames.Add(e);
+				globalFilenames = db.Entries;
 
-			var package = new MixLoader.MixFile(File.OpenRead(args[1]), args[1], allPossibleFilenames);
+			var package = new MixLoader.MixFile(File.OpenRead(args[1]), args[1], globalFilenames);
 			foreach (var kv in package.Index.OrderBy(kv => kv.Value.Offset))
 			{
 				Console.WriteLine("{0}:", kv.Key);