diff --git a/DepotDownloader/ContentDownloader.cs b/DepotDownloader/ContentDownloader.cs
index 23d167df..209fa9bb 100644
--- a/DepotDownloader/ContentDownloader.cs
+++ b/DepotDownloader/ContentDownloader.cs
@@ -94,12 +94,13 @@ namespace DepotDownloader
             if ( !Config.UsingFileList )
                 return true;
 
-            foreach ( string fileListEntry in Config.FilesToDownload )
+            filename = filename.Replace( '\\', '/' );
+            
+            if ( Config.FilesToDownload.Contains( filename ) )
             {
-                if ( fileListEntry.Equals( filename, StringComparison.OrdinalIgnoreCase ) )
-                    return true;
+                return true;
             }
-
+            
             foreach ( Regex rgx in Config.FilesToDownloadRegex )
             {
                 Match m = rgx.Match( filename );
diff --git a/DepotDownloader/DownloadConfig.cs b/DepotDownloader/DownloadConfig.cs
index 2d27bf26..14d1638c 100644
--- a/DepotDownloader/DownloadConfig.cs
+++ b/DepotDownloader/DownloadConfig.cs
@@ -12,7 +12,7 @@ namespace DepotDownloader
         public string InstallDirectory { get; set; }
 
         public bool UsingFileList { get; set; }
-        public List<string> FilesToDownload { get; set; }
+        public HashSet<string> FilesToDownload { get; set; }
         public List<Regex> FilesToDownloadRegex { get; set; }
 
         public string BetaPassword { get; set; }
diff --git a/DepotDownloader/Program.cs b/DepotDownloader/Program.cs
index c522c7e4..cf7b0f33 100644
--- a/DepotDownloader/Program.cs
+++ b/DepotDownloader/Program.cs
@@ -53,48 +53,28 @@ namespace DepotDownloader
             ContentDownloader.Config.CellID = cellId;
 
             string fileList = GetParameter<string>( args, "-filelist" );
-            string[] files = null;
 
             if ( fileList != null )
             {
                 try
                 {
-                    string fileListData = File.ReadAllText(fileList);
-                    files = fileListData.Split( new char[] { '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries );
+                    string fileListData = await File.ReadAllTextAsync( fileList );
+                    var files = fileListData.Split( new char[] { '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries );
 
                     ContentDownloader.Config.UsingFileList = true;
-                    ContentDownloader.Config.FilesToDownload = new List<string>();
+                    ContentDownloader.Config.FilesToDownload = new HashSet<string>( StringComparer.OrdinalIgnoreCase );
                     ContentDownloader.Config.FilesToDownloadRegex = new List<Regex>();
-
-                    var isWindows = RuntimeInformation.IsOSPlatform( OSPlatform.Windows );
+                    
                     foreach ( var fileEntry in files )
                     {
-                        try
+                        if ( fileEntry.StartsWith( "regex:" ) )
                         {
-                            string fileEntryProcessed;
-                            if ( isWindows )
-                            {
-                                // On Windows, ensure that forward slashes can match either forward or backslashes in depot paths
-                                fileEntryProcessed = fileEntry.Replace( "/", "[\\\\|/]" );
-                            }
-                            else
-                            {
-                                // On other systems, treat / normally
-                                fileEntryProcessed = fileEntry;
-                            }
-                            Regex rgx = new Regex( fileEntryProcessed, RegexOptions.Compiled | RegexOptions.IgnoreCase );
+                            Regex rgx = new Regex( fileEntry.Substring( 6 ), RegexOptions.Compiled | RegexOptions.IgnoreCase );
                             ContentDownloader.Config.FilesToDownloadRegex.Add( rgx );
                         }
-                        catch
+                        else
                         {
-                            // For anything that can't be processed as a Regex, allow both forward and backward slashes to match
-                            // on Windows
-                            if( isWindows )
-                            {
-                                ContentDownloader.Config.FilesToDownload.Add( fileEntry.Replace( "/", "\\" ) );
-                            }
-                            ContentDownloader.Config.FilesToDownload.Add( fileEntry );
-                            continue;
+                            ContentDownloader.Config.FilesToDownload.Add( fileEntry.Replace( '\\', '/' ) );
                         }
                     }
 
@@ -403,7 +383,7 @@ namespace DepotDownloader
             Console.WriteLine( "\t-remember-password\t\t- if set, remember the password for subsequent logins of this user." );
             Console.WriteLine();
             Console.WriteLine( "\t-dir <installdir>\t\t- the directory in which to place downloaded files." );
-            Console.WriteLine( "\t-filelist <file.txt>\t- a list of files to download (from the manifest). Can optionally use regex to download only certain files." );
+            Console.WriteLine( "\t-filelist <file.txt>\t- a list of files to download (from the manifest). Prefix file path with 'regex:' if you want to match with regex." );
             Console.WriteLine( "\t-validate\t\t\t\t- Include checksum verification of files already downloaded" );
             Console.WriteLine();
             Console.WriteLine( "\t-manifest-only\t\t\t- downloads a human readable manifest for any depots that would be downloaded." );
diff --git a/README.md b/README.md
index e71b5519..f08783fb 100644
--- a/README.md
+++ b/README.md
@@ -46,7 +46,7 @@ Parameter | Description
 -password \<pass>		| the password of the account to login to for restricted content.
 -remember-password		| if set, remember the password for subsequent logins of this user.
 -dir \<installdir>		| the directory in which to place downloaded files.
--filelist \<file.txt>	| a list of files to download (from the manifest). Can optionally use regex to download only certain files.
+-filelist \<file.txt>	| a list of files to download (from the manifest). Prefix file path with `regex:` if you want to match with regex.
 -validate				| Include checksum verification of files already downloaded
 -manifest-only			| downloads a human readable manifest for any depots that would be downloaded.
 -cellid \<#>			| the overridden CellID of the content server to download from.