diff --git a/frontend/src/api/connection-manager.ts b/frontend/src/api/connection-manager.ts
index be832e9..9555028 100644
--- a/frontend/src/api/connection-manager.ts
+++ b/frontend/src/api/connection-manager.ts
@@ -318,7 +318,8 @@ class ConnectionManagerImpl {
     try {
       await this.buildAndPool(profileId, profile)
     } catch (err) {
-      this._activeId = prevActiveId
+      // 回退目标可能已不在池中（死连接重建时 disconnectProfile 先移除），指向池外会让 getTransport 静默回落本地造成 UI 幻影
+      this._activeId = (prevActiveId && this._pool.has(prevActiveId)) ? prevActiveId : 'local-default'
       this.setProfileState(profileId, 'error', err instanceof Error ? err.message : String(err))
       this.notifyChange()
       throw err
diff --git a/frontend/src/components/FileSystem/index.vue b/frontend/src/components/FileSystem/index.vue
index b758b53..f6aaa70 100644
--- a/frontend/src/components/FileSystem/index.vue
+++ b/frontend/src/components/FileSystem/index.vue
@@ -992,6 +992,12 @@ const handlePasteClipboard = async () => {
   const targetDir = filePath.value
   if (!targetDir) return
 
+  // 剪切源即目标目录时无操作（继续执行会把源文件改名成副本），Explorer 语义是清空剪贴板
+  if (clip.mode === 'cut' && clip.fromDir === targetDir) {
+    clearClipboard()
+    return
+  }
+
   let failed = 0
   for (const item of clip.items) {
     const dstName = uniqueNameInList(item.name)
diff --git a/internal/oss/aliyun/client.go b/internal/oss/aliyun/client.go
index 411e96d..6f5d606 100644
--- a/internal/oss/aliyun/client.go
+++ b/internal/oss/aliyun/client.go
@@ -489,7 +489,8 @@ func (c *Client) GetSignedURL(ctx context.Context, key string, expiresIn time.Du
 	stringToSign := "GET\n\n\n" + fmt.Sprintf("%d", expiration) + "\n" + path
 	h := hmac.New(sha1.New, []byte(c.config.AccessKeySecret))
 	h.Write([]byte(stringToSign))
-	signature := base64.URLEncoding.EncodeToString(h.Sum(nil))
+	// 阿里云签名规范是标准 base64 字母表并保留 padding，= 由下方 QueryEscape 转义
+	signature := base64.StdEncoding.EncodeToString(h.Sum(nil))
 
 	scheme := "https://"
 	if !c.config.UseHTTPS {
diff --git a/internal/sftp/service.go b/internal/sftp/service.go
index b5a7149..f13ca5d 100644
--- a/internal/sftp/service.go
+++ b/internal/sftp/service.go
@@ -632,7 +632,10 @@ func (s *Service) downloadFileTo(c *Client, remotePath, localPath string, copied
 	if err := os.MkdirAll(filepath.Dir(localPath), 0755); err != nil {
 		return fmt.Errorf("创建本地目录失败: %w", err)
 	}
+	// 重试会整文件重写，进度须回到进入前基线，否则跨重试累计使 copied 超过 total
+	base := *copied
 	return c.WithRetry(func(sc *sftpclient.Client) error {
+		*copied = base
 		src, err := sc.Open(remotePath)
 		if err != nil {
 			return err
@@ -722,7 +725,10 @@ func (s *Service) UploadFromFile(connID, localPath, remoteDir string, onProgress
 
 // uploadFileTo 流式上传单个本地文件（自动创建远端父目录），进度按累计字节回调
 func (s *Service) uploadFileTo(c *Client, localPath, remotePath string, copied *int64, total int64, onProgress func(fileName string, copied, total int64)) error {
+	// 重试会整文件重传，进度须回到进入前基线，否则跨重试累计使 copied 超过 total
+	base := *copied
 	return c.WithRetry(func(sc *sftpclient.Client) error {
+		*copied = base
 		if err := sc.MkdirAll(path.Dir(remotePath)); err != nil {
 			return err
 		}