diff --git a/PCL.Core/App/Localization/Languages/en-US.xaml b/PCL.Core/App/Localization/Languages/en-US.xaml
index c090e7a13e..2ab64259ad 100644
--- a/PCL.Core/App/Localization/Languages/en-US.xaml
+++ b/PCL.Core/App/Localization/Languages/en-US.xaml
@@ -598,7 +598,7 @@
 
     <sys:String x:Key="Download.Comp.QuickDownload.Btn.ToolTip">Download the latest version</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseInstance.Title">Select a target Minecraft instance</sys:String>
-    <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.AskInstance">Select an instance…</sys:String>
+    <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.AskInstance">Select instances…</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.AskPath">Select a folder…</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.CurrentInstance">Download to the current instance</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.Title">Select a download destination</sys:String>
diff --git a/PCL.Core/App/Localization/Languages/zh-CN.xaml b/PCL.Core/App/Localization/Languages/zh-CN.xaml
index 9bae29f93c..0d6318c996 100644
--- a/PCL.Core/App/Localization/Languages/zh-CN.xaml
+++ b/PCL.Core/App/Localization/Languages/zh-CN.xaml
@@ -598,7 +598,7 @@
 
     <sys:String x:Key="Download.Comp.QuickDownload.Btn.ToolTip">快速下载最新版本</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseInstance.Title">选择要下载到的 Minecraft 实例</sys:String>
-    <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.AskInstance">选择一个实例…</sys:String>
+    <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.AskInstance">选择实例…</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.AskPath">选择一个文件夹…</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.CurrentInstance">下载到当前选中实例</sys:String>
     <sys:String x:Key="Download.Comp.QuickDownload.ChooseMethod.Title">选择下载方式</sys:String>
diff --git a/Plain Craft Launcher 2/Controls/MyMsg/MyMsgSelect.xaml.cs b/Plain Craft Launcher 2/Controls/MyMsg/MyMsgSelect.xaml.cs
index c489762258..d978020881 100644
--- a/Plain Craft Launcher 2/Controls/MyMsg/MyMsgSelect.xaml.cs	
+++ b/Plain Craft Launcher 2/Controls/MyMsg/MyMsgSelect.xaml.cs	
@@ -1,4 +1,4 @@
-using System.Collections;
+using System.Collections;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
@@ -82,11 +82,13 @@ private void InitializeSelectionList(object content)
             {
                 PanSelection.Children.Add((UIElement)selection);
                 selection.Check += (sender, e) => OnChecked((IMyRadio)sender, e);
+                selection.Changed += (_, _) => _UpdateCheckedState();
 
                 // 3. Property configuration based on specific type
                 if (selection is MyListItem listItem)
                 {
-                    listItem.Type = MyListItem.CheckType.RadioBox;
+                    listItem.Type =
+                        myConverter.MultiSelect ? MyListItem.CheckType.CheckBox : MyListItem.CheckType.RadioBox;
                     listItem.MinHeight = 24.0;
                 }
                 else if (selection is MyRadioBox radioBox)
@@ -163,10 +165,26 @@ private void Close()
 
     public void Btn1_Click(object sender, MouseButtonEventArgs e)
     {
-        if (myConverter.IsExited || selectedIndex == -1)
+        if (myConverter.IsExited)
             return;
-        myConverter.IsExited = true;
-        myConverter.Result = selectedIndex;
+        if (myConverter.MultiSelect)
+        {
+            var indices = new List<int>();
+            for (var i = 0; i < PanSelection.Children.Count; i++)
+                if (PanSelection.Children[i] is MyListItem { Checked: true })
+                    indices.Add(i);
+            if (indices.Count == 0)
+                return;
+            myConverter.IsExited = true;
+            myConverter.Result = indices;
+        }
+        else
+        {
+            if (selectedIndex == -1)
+                return;
+            myConverter.IsExited = true;
+            myConverter.Result = selectedIndex;
+        }
         Close();
     }
 
@@ -181,10 +199,24 @@ public void Btn2_Click(object sender, MouseButtonEventArgs e)
 
     private void OnChecked(IMyRadio sender, EventArgs e)
     {
+        if (myConverter.MultiSelect)
+            return;
         Btn1.IsEnabled = true;
         selectedIndex = PanSelection.Children.IndexOf((UIElement)sender);
     }
 
+    private void _UpdateCheckedState()
+    {
+        // 多选
+        if (!myConverter.MultiSelect)
+            return;
+        var checkedCount = 0;
+        foreach (var child in PanSelection.Children)
+            if (child is MyListItem { Checked: true })
+                checkedCount += 1;
+        Btn1.IsEnabled = checkedCount > 0;
+    }
+
     private void Drag(object sender, MouseButtonEventArgs e)
     {
         try
diff --git a/Plain Craft Launcher 2/Modules/Minecraft/ModComp.cs b/Plain Craft Launcher 2/Modules/Minecraft/ModComp.cs
index 771943c813..be64a00ea3 100644
--- a/Plain Craft Launcher 2/Modules/Minecraft/ModComp.cs	
+++ b/Plain Craft Launcher 2/Modules/Minecraft/ModComp.cs	
@@ -3540,9 +3540,11 @@ public static void QuickDownload(CompProject project)
                         break;
                     case 2: // 询问并下载到选择的实例
                     {
-                        var instance = _QuickDownloadPickInstance(project, files);
-                        if (instance is null) return;
-                        _QuickDownloadToInstance(project, files, instance);
+                        var instances = _QuickDownloadPickInstances(project, files);
+                        if (instances is null) return;
+                        var startedTargets = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+                        foreach (var instance in instances)
+                            _QuickDownloadToInstance(project, files, instance, startedTargets);
                         break;
                     }
                     case 3: // 询问并下载到一个路径
@@ -3562,7 +3564,8 @@ public static void QuickDownload(CompProject project)
     }
 
     /// <summary>下载到指定实例的最新兼容版本。</summary>
-    private static void _QuickDownloadToInstance(CompProject project, List<CompFile> files, McInstance? instance)
+    private static void _QuickDownloadToInstance(CompProject project, List<CompFile> files, McInstance? instance,
+        ISet<string>? startedTargets = null)
     {
         if (instance is null)
         {
@@ -3582,12 +3585,15 @@ private static void _QuickDownloadToInstance(CompProject project, List<CompFile>
         var folder = instance.PathIndie + _GetSubFolder(project.Type);
         Directory.CreateDirectory(folder);
         var target = Path.Combine(folder, CompFileNameGet(project, file));
+        //只下载一次，避免并发写同一文件
+        if (startedTargets is not null && !startedTargets.Add(target))
+            return;
         _StartQuickDownload(file, target);
         HintService.Hint(Lang.Text("Download.Comp.QuickDownload.Hint.DownloadStarted", project.RawName), HintType.Success);
     }
 
     /// <summary>弹实例列表让用户选择，返回选中的实例（兼容者优先、当前选中实例居首）；取消或无兼容实例返回 null。</summary>
-    private static McInstance? _QuickDownloadPickInstance(CompProject project, List<CompFile> files)
+    private static List<McInstance>? _QuickDownloadPickInstances(CompProject project, List<CompFile> files)
     {
         var needLoad = ModInstanceList.mcInstanceListLoader.State != ModBase.LoadState.Finished;
         if (needLoad)
@@ -3612,18 +3618,18 @@ private static void _QuickDownloadToInstance(CompProject project, List<CompFile>
                 .OrderBy(v => v == current ? 0 : 1)
                 .ThenBy(v => v.Name)
                 .ToList();
-        int? idx = ModBase.RunInUiWait(() =>
+        var indices = ModBase.RunInUiWait(() =>
         {
             var options = compatible
-                .Select(v => (IMyRadio)new MyRadioBox { Text = v.Name })
+                .Select(v => new MyListItem { Title = v.Name })
                 .ToList();
-            return ModMain.MyMsgBoxSelect(options,
+            return ModMain.MyMsgBoxMultiSelect(options,
                 Lang.Text("Download.Comp.QuickDownload.ChooseInstance.Title"),
                 button1: Lang.Text("Common.Action.Continue"),
                 button2: Lang.Text("Common.Action.Cancel"));
         });
-        if (idx is null) return null;
-        return compatible[idx.Value];
+        if (indices is null) return null;
+        return indices.Select(i => compatible[i]).ToList();
     }
 
     /// <summary>下载最新版本到用户选择的文件夹。</summary>
diff --git a/Plain Craft Launcher 2/Modules/ModMain.cs b/Plain Craft Launcher 2/Modules/ModMain.cs
index c1ecd882a1..f33362a7bb 100644
--- a/Plain Craft Launcher 2/Modules/ModMain.cs	
+++ b/Plain Craft Launcher 2/Modules/ModMain.cs	
@@ -1,4 +1,4 @@
-using System.Collections;
+using System.Collections;
 using System.Collections.ObjectModel;
 using System.IO;
 using System.Runtime.InteropServices;
@@ -262,6 +262,11 @@ public class MyMsgBoxConverter
 
         public bool ForceWait;
 
+        /// <summary>
+        ///     选择模式：是否允许勾选多个选项
+        /// </summary>
+        public bool MultiSelect;
+
         /// <summary>
         ///     有多个按钮时，是否给第一个按钮加高亮。
         /// </summary>
@@ -581,6 +586,44 @@ public static string MyMsgBoxInput(string title, string text = "", string defaul
         return (int?)converter.Result;
     }
 
+    /// <summary>
+    ///     显示多选选择框并返回勾选的所有项索引（从 0 开始）。若点击第二个按钮，则返回 Nothing。
+    /// </summary>
+    /// <param name="selections">需要展示的可勾选列表项。</param>
+    /// <param name="title">弹窗的标题。</param>
+    /// <param name="button1">显示的第一个按钮，默认为 “确定”。</param>
+    /// <param name="button2">显示的第二个按钮，默认为空。</param>
+    /// <param name="isWarn">是否为警告弹窗，若为 True，弹窗配色和背景会变为红色。</param>
+    public static List<int>? MyMsgBoxMultiSelect(List<MyListItem> selections, string? title = null,
+        string? button1 = null, string? button2 = "", bool isWarn = false)
+    {
+        title ??= GetDefaultDialogTitle();
+        button1 ??= GetDefaultConfirmText();
+        button2 ??= "";
+        // 将弹窗列入队列
+        var converter = new MyMsgBoxConverter
+        {
+            Type = MyMsgBoxType.Select, MultiSelect = true, Button1 = button1, Button2 = button2, Content = selections,
+            IsWarn = isWarn, Title = title
+        };
+        WaitingMyMsgBox.Add(converter);
+        // 虽然我也不知道这是啥但是能用就成了 :)
+        try
+        {
+            if (frmMain is not null)
+                frmMain.DragStop();
+            ComponentDispatcher.PushModal();
+            Dispatcher.PushFrame(converter.WaitFrame);
+        }
+        finally
+        {
+            ComponentDispatcher.PopModal();
+        }
+
+        ModBase.Log($"[Control] 多选弹框返回：{converter.Result ?? "null"}");
+        return (List<int>?)converter.Result;
+    }
+
 
     public static void MyMsgBoxTick()
     {