diff --git a/AssetStudio/AssetsManager.cs b/AssetStudio/AssetsManager.cs
index fe6f293..835ed88 100644
--- a/AssetStudio/AssetsManager.cs
+++ b/AssetStudio/AssetsManager.cs
@@ -270,7 +270,7 @@ namespace AssetStudio
                     assetsFile.originalPath = originalPath;
                     if (assetBundleUnityVer != null && assetsFile.header.m_Version < SerializedFileFormatVersion.Unknown_7)
                     {
-                        assetsFile.SetVersion(assetBundleUnityVer);
+                        assetsFile.version = assetBundleUnityVer;
                     }
                     CheckStrippedVersion(assetsFile, assetBundleUnityVer);
                     assetsFileList.Add(assetsFile);
@@ -487,7 +487,7 @@ namespace AssetStudio
             }
             if (specifiedUnityVersion != null)
             {
-                assetsFile.SetVersion(SpecifyUnityVersion);
+                assetsFile.version = SpecifyUnityVersion;
             }
         }
 
diff --git a/AssetStudio/SerializedFile.cs b/AssetStudio/SerializedFile.cs
index e10c38b..af6183c 100644
--- a/AssetStudio/SerializedFile.cs
+++ b/AssetStudio/SerializedFile.cs
@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
-using System.Text.RegularExpressions;
 
 namespace AssetStudio
 {
@@ -19,7 +17,6 @@ namespace AssetStudio
 
         public SerializedFileHeader header;
         private byte m_FileEndianess;
-        public string unityVersion = "2.5.0f5";
         public BuildTarget m_TargetPlatform = BuildTarget.UnknownPlatform;
         private bool m_EnableTypeTree = true;
         public List<SerializedType> m_Types;
@@ -71,8 +68,11 @@ namespace AssetStudio
             }
             if (header.m_Version >= SerializedFileFormatVersion.Unknown_7)
             {
-                unityVersion = reader.ReadStringToNull();
-                SetVersion(new UnityVersion(unityVersion));
+                version = new UnityVersion(reader.ReadStringToNull());
+            }
+            else
+            {
+                version = new UnityVersion(2, 5, 0);
             }
             if (header.m_Version >= SerializedFileFormatVersion.Unknown_8)
             {
@@ -216,15 +216,6 @@ namespace AssetStudio
             //reader.AlignStream(16);
         }
 
-        public void SetVersion(UnityVersion unityVer)
-        {
-            if (unityVer != null && !unityVer.IsStripped)
-            {
-                unityVersion = unityVer.FullVersion;
-                version = unityVer;
-            }
-        }
-
         private SerializedType ReadSerializedType(bool isRefType)
         {
             var type = new SerializedType();
diff --git a/AssetStudio/UnityVersion.cs b/AssetStudio/UnityVersion.cs
index 6c2ac0d..ae62d52 100644
--- a/AssetStudio/UnityVersion.cs
+++ b/AssetStudio/UnityVersion.cs
@@ -38,7 +38,7 @@ namespace AssetStudio
             {
                 int[] ver = Regex.Matches(version, @"\d+").Cast<Match>().Select(x => int.Parse(x.Value)).ToArray();
                 (Major, Minor, Patch) = (ver[0], ver[1], ver[2]);
-                if (ver.Length == 4)
+                if (ver.Length >= 4)
                     Build = ver[3];
                 FullVersion = version;
             }
diff --git a/AssetStudioGUI/AssetStudioGUIForm.cs b/AssetStudioGUI/AssetStudioGUIForm.cs
index 8eb896d..13edb3a 100644
--- a/AssetStudioGUI/AssetStudioGUIForm.cs
+++ b/AssetStudioGUI/AssetStudioGUIForm.cs
@@ -266,7 +266,7 @@ namespace AssetStudioGUI
             var typeMap = await Task.Run(() => BuildClassStructure());
             productName = string.IsNullOrEmpty(productName) ? "no productName" : productName;
 
-            Text = $"{guiTitle} - {productName} - {assetsManager.assetsFileList[0].unityVersion} - {assetsManager.assetsFileList[0].m_TargetPlatform}";
+            Text = $"{guiTitle} - {productName} - {assetsManager.assetsFileList[0].version} - {assetsManager.assetsFileList[0].m_TargetPlatform}";
 
             assetListView.VirtualListSize = visibleAssets.Count;
 
@@ -278,7 +278,7 @@ namespace AssetStudioGUI
             classesListView.BeginUpdate();
             foreach (var version in typeMap)
             {
-                var versionGroup = new ListViewGroup(version.Key);
+                var versionGroup = new ListViewGroup(version.Key.FullVersion);
                 classesListView.Groups.Add(versionGroup);
 
                 foreach (var uclass in version.Value)
diff --git a/AssetStudioGUI/Studio.cs b/AssetStudioGUI/Studio.cs
index 34542f2..9ac0237 100644
--- a/AssetStudioGUI/Studio.cs
+++ b/AssetStudioGUI/Studio.cs
@@ -429,12 +429,12 @@ namespace AssetStudioGUI
             return (productName, treeNodeCollection);
         }
 
-        public static Dictionary<string, SortedDictionary<int, TypeTreeItem>> BuildClassStructure()
+        public static Dictionary<UnityVersion, SortedDictionary<int, TypeTreeItem>> BuildClassStructure()
         {
-            var typeMap = new Dictionary<string, SortedDictionary<int, TypeTreeItem>>();
+            var typeMap = new Dictionary<UnityVersion, SortedDictionary<int, TypeTreeItem>>();
             foreach (var assetsFile in assetsManager.assetsFileList)
             {
-                if (typeMap.TryGetValue(assetsFile.unityVersion, out var curVer))
+                if (typeMap.TryGetValue(assetsFile.version, out var curVer))
                 {
                     foreach (var type in assetsFile.m_Types.Where(x => x.m_Type != null))
                     {
@@ -458,7 +458,7 @@ namespace AssetStudioGUI
                         }
                         items[key] = new TypeTreeItem(key, type.m_Type);
                     }
-                    typeMap.Add(assetsFile.unityVersion, items);
+                    typeMap.Add(assetsFile.version, items);
                 }
             }
             return typeMap;