diff --git a/MifareOneTool.sln b/MifareOneTool.sln
index 90f9a52..80faf27 100644
--- a/MifareOneTool.sln
+++ b/MifareOneTool.sln
@@ -3,8 +3,6 @@ Microsoft Visual Studio Solution File, Format Version 11.00
 # Visual Studio 2010
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MifareOneTool", "MifareOneTool\MifareOneTool.csproj", "{CDB26016-FC77-403F-B22A-A011F8622FCF}"
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "DirectOP", "DirectOP\DirectOP.vcxproj", "{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}"
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -29,18 +27,6 @@ Global
 		{CDB26016-FC77-403F-B22A-A011F8622FCF}.Release|Win32.ActiveCfg = Release|x86
 		{CDB26016-FC77-403F-B22A-A011F8622FCF}.Release|x86.ActiveCfg = Release|x86
 		{CDB26016-FC77-403F-B22A-A011F8622FCF}.Release|x86.Build.0 = Release|x86
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Debug|Any CPU.ActiveCfg = Debug|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Debug|Mixed Platforms.ActiveCfg = Debug|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Debug|Mixed Platforms.Build.0 = Debug|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Debug|Win32.ActiveCfg = Debug|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Debug|Win32.Build.0 = Debug|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Debug|x86.ActiveCfg = Debug|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Release|Any CPU.ActiveCfg = Release|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Release|Mixed Platforms.ActiveCfg = Release|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Release|Mixed Platforms.Build.0 = Release|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Release|Win32.ActiveCfg = Release|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Release|Win32.Build.0 = Release|Win32
-		{E17E8EAB-394B-4907-97CB-7CDFF40B3F78}.Release|x86.ActiveCfg = Release|Win32
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/MifareOneTool/ClassMifareS50.cs b/MifareOneTool/ClassMifareS50.cs
index c32660b..4faf112 100644
--- a/MifareOneTool/ClassMifareS50.cs
+++ b/MifareOneTool/ClassMifareS50.cs
@@ -374,7 +374,8 @@ namespace MifareOneTool
         public void LoadFromMctTxt(string file)
         {
             if (!File.Exists(file)) { throw new IOException("加载的文件不存在。"); }
-            if (new FileInfo(file).Length < 2300 || new FileInfo(file).Length > 2400) { throw new IOException("加载的S50卡文件大小异常。"); }
+            long fileLength=new FileInfo(file).Length;
+            if (fileLength < 2200 || fileLength > 2400) { throw new IOException("加载的S50卡文件大小异常。"); }
             List<string> lines = new List<string>(File.ReadAllLines(file));
             List<string> invaild = new List<string>();
             foreach (string line in lines)