diff --git a/README.md b/README.md
index 71f7cf1..ff708a9 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,10 @@ curl -fsSL https://raw.githubusercontent.com/zxyszx/NewSzxcn-Email/main/install.
 bash <(curl -fsSL https://raw.githubusercontent.com/zxyszx/NewSzxcn-Email/main/install.sh)
 ```
 
+空白服务器会进入防火墙、邮件域名、管理员账号和 Web 部署方式的引导。检测到
+`/opt/newszxcn-email/.env` 时，脚本会先询问是更新现有邮局、修复现有安装还是退出；
+不会再直接跳过引导并重启服务。更新会先备份数据库，并在启动失败时自动回滚。
+
 脚本会自动完成：
 
 - 安装或检查 Docker Engine 与 Docker Compose v2
diff --git a/install.sh b/install.sh
index 3b6c56b..a4d05e7 100755
--- a/install.sh
+++ b/install.sh
@@ -21,7 +21,7 @@ NewSzxcn Email 管理命令
 
 用法：newszxcn-email <command>
 
-  install     首次安装或修复部署
+  install     首次安装；检测到已有安装时显示操作菜单
   update      备份数据库并更新到最新版
   status      查看容器与健康状态
   logs        持续查看运行日志
@@ -163,6 +163,21 @@ prompt_choice() {
   done
 }
 
+prompt_existing_install_action() {
+  local public_url action
+  public_url="$(env_value LANQIN_PUBLIC_BASE_URL || true)"
+  prompt_text "\n[发现] 检测到已有 NewSzxcn Email 安装：${INSTALL_DIR}\n"
+  if [[ -n "${public_url}" ]]; then
+    prompt_text "[发现] 当前访问地址：${public_url}\n"
+  fi
+  prompt_text '请选择操作 [1]：\n1. 更新现有邮局（推荐，自动备份并支持回滚）\n2. 修复现有安装（保留配置和数据）\n3. 退出，不做任何修改\n'
+  if [[ -z "${LANQIN_EXISTING_ACTION:-}" ]] && ! has_tty; then
+    fail "非交互环境不能选择已有安装操作；更新请执行 newszxcn-email update。"
+  fi
+  action="$(prompt_choice LANQIN_EXISTING_ACTION "请选择 [1]: " "1")"
+  printf '%s' "${action}"
+}
+
 has_tty() {
   [[ -e /dev/tty ]] && (: </dev/tty) 2>/dev/null
 }
@@ -562,7 +577,45 @@ remember_current_image() {
   printf '%s\n' "${rollback_tag}" > "${ROLLBACK_FILE}"
 }
 
+do_repair_install() {
+  refresh_assets
+  ensure_update_token
+  configure_runtime_bindings
+  ensure_docker
+  backup_database
+  remember_current_image
+  configure_firewall
+  prepare_directories
+  log "正在拉取并修复 NewSzxcn Email 服务..."
+  compose pull
+  log "正在启动服务..."
+  if ! compose up -d --remove-orphans; then
+    warn "修复后容器启动失败，正在自动回滚。"
+    do_rollback
+    fail "修复失败，已回滚到原镜像。"
+  fi
+  if ! wait_for_health 90; then
+    warn "修复后健康检查失败，正在自动回滚。"
+    do_rollback
+    fail "修复失败，已回滚到原镜像。"
+  fi
+  configure_web_mode
+  success "安装完成：$(env_value LANQIN_PUBLIC_BASE_URL)"
+  warn "下一步请配置 MX、SPF、DKIM、DMARC，并确认 25/465/587/993/995 端口可访问。"
+}
+
 do_install() {
+  local action
+  if [[ -f "${INSTALL_DIR}/.env" ]]; then
+    action="$(prompt_existing_install_action)"
+    case "${action}" in
+      1) do_update ;;
+      2) do_repair_install ;;
+      3) success "已退出，现有邮局未作修改。" ;;
+    esac
+    return
+  fi
+
   refresh_assets
   configure_first_install
   ensure_update_token
diff --git a/tests/install_test.sh b/tests/install_test.sh
index 8a25410..3a4342d 100644
--- a/tests/install_test.sh
+++ b/tests/install_test.sh
@@ -109,6 +109,22 @@ test_legacy_configuration_is_preserved() {
   assert_eq "127.0.0.1:9090" "$(env_value LANQIN_HTTP_BIND)" "legacy HTTP bind"
 }
 
+test_existing_install_action() {
+  local temp_dir
+  temp_dir="$(mktemp -d)"
+  cp "${ROOT_DIR}/deploy/.env.example" "${temp_dir}/.env"
+  export INSTALL_DIR="${temp_dir}"
+  set_env LANQIN_PUBLIC_BASE_URL "https://mail.example.com"
+
+  export LANQIN_EXISTING_ACTION=1
+  assert_eq "1" "$(prompt_existing_install_action)" "existing install update action"
+  export LANQIN_EXISTING_ACTION=2
+  assert_eq "2" "$(prompt_existing_install_action)" "existing install repair action"
+  export LANQIN_EXISTING_ACTION=3
+  assert_eq "3" "$(prompt_existing_install_action)" "existing install exit action"
+  unset LANQIN_EXISTING_ACTION
+}
+
 test_hostname_validation
 test_password_validation
 test_install_configuration 1 1 "127.0.0.1:8088" "https://mail.example.com" "false"
@@ -117,5 +133,6 @@ test_install_configuration 3 3 "80" "http://mail.example.com" "true"
 test_nginx_configuration
 test_compose_configuration
 test_legacy_configuration_is_preserved
+test_existing_install_action
 
 printf 'install.sh tests passed\n'