--- a/wechat_rpa/archive_auto_backup.py
+++ b/wechat_rpa/archive_auto_backup.py
@@ -271,27 +271,21 @@
 
 
 def _api_candidates(explicit: str = "") -> list[str]:
-    values: list[str] = []
+    """安装版沿用登录云端；源码模式保留显式开发地址。"""
+    if is_frozen():
+        return [backend_client.resolve_backend_url()]
     configured = explicit or os.environ.get("WECOM_ARCHIVE_API_URL", "").strip()
     if configured:
-        values.append(configured.rstrip("/"))
+        return [backend_client.normalize_server_url(configured)]
     try:
-        server_url = str(backend_client.load_settings().get("server_url") or "").rstrip("/")
+        saved = backend_client.load_settings().get("server_url")
     except Exception:
-        server_url = ""
-    if server_url:
-        parsed = urlparse(server_url)
-        if parsed.port == 8766:
-            values.append(server_url)
-        if parsed.hostname in {"127.0.0.1", "localhost", "::1"}:
-            values.append(_with_port(server_url, 8766))
-    values.append("http://127.0.0.1:8766")
-    result: list[str] = []
-    for value in values:
-        normalized = str(value or "").strip().rstrip("/")
-        if normalized and normalized not in result:
-            result.append(normalized)
-    return result
+        saved = None
+    server_url = backend_client.resolve_backend_url(saved)
+    values = [server_url]
+    if urlparse(server_url).hostname in {"127.0.0.1", "localhost", "::1"}:
+        values.append(_with_port(server_url, 8766))
+    return list(dict.fromkeys(value for value in values if value))
 
 
 @dataclass(frozen=True)
@@ -1500,6 +1494,35 @@
     return result
 
 
+def _prepare_archive_databases(config: AutoBackupConfig) -> list[tuple[str, str, str]]:
+    """后台归档复用桌面密钥与 WAL 解密器。"""
+    import wxwork_db
+    from wxwork_local_setup import acquire_local_keys, select_source_directory
+
+    try:
+        keys = _load_exporter_keys(config.exporter_root)
+    except ArchiveBackupError:
+        keys = {}
+    try:
+        keys.update(wxwork_db.load_keys())
+    except ValueError:
+        pass
+    output = str(config.work_root / "decrypted")
+    decrypted = wxwork_db.decrypt_with_keys(str(config.source_root), output, keys, use_cache=True)
+    if any(name == "message.db" for _, name, _ in decrypted):
+        return decrypted
+    select_source_directory(str(config.source_root))
+    try:
+        acquire_local_keys()
+    except (OSError, ValueError) as exc:
+        raise ArchiveBackupError(f"自动获取数据库密钥失败：{exc}；可到微信消息库手动处理") from exc
+    keys.update(wxwork_db.load_keys())
+    decrypted = wxwork_db.decrypt_with_keys(str(config.source_root), output, keys, use_cache=True)
+    if not any(name == "message.db" for _, name, _ in decrypted):
+        raise ArchiveBackupError("没有解密出可用的企业微信 message.db，请检查数据目录和密钥")
+    return decrypted
+
+
 def run_backup_once(config: AutoBackupConfig) -> dict[str, Any]:
     # 子进程真正执行时再校验一次，覆盖软件启动后路径迁移或磁盘重连的情况。
     detected_source_root = _configured_source_root(
@@ -1527,15 +1550,7 @@
                     f"最后检查路径：{config.source_root}"
                 )
             exporter, media_exporter = _load_exporter_modules(config.exporter_root)
-            keys = _load_exporter_keys(config.exporter_root)
-            decrypted = exporter.decrypt_with_keys(
-                str(config.source_root),
-                str(config.work_root / "decrypted"),
-                keys,
-                use_cache=True,
-            )
-            if not any(item[1] == "message.db" for item in decrypted):
-                raise ArchiveBackupError("没有解密出可用的企业微信 message.db")
+            decrypted = _prepare_archive_databases(config)
             api = ArchiveApiClient.connect(config.api_urls)
             summary = IncrementalArchiveImporter(
                 config, api, exporter, media_exporter
@@ -1674,13 +1689,14 @@
                     log.write("自动增量备份已由后台停用\n")
                 next_run = None
                 last_interval = interval
-            elif next_run is None or interval != last_interval:
-                next_run = now + interval * 60
+            elif next_run is None:
+                next_run = now
                 last_interval = interval
-                log.write(
-                    f"自动增量备份已排期：{interval} 分钟后执行，之后每 {interval} 分钟一次\n"
-                )
-            elif now >= next_run:
+                log.write(f"自动增量备份立即启动，之后每 {interval} 分钟一次\n")
+            elif interval != last_interval:
+                next_run = min(next_run, now + interval * 60)
+                last_interval = interval
+            if enabled and next_run is not None and now >= next_run:
                 _run_worker_with_retries(config, log_path)
                 # 一轮可能运行很久，从完成时刻重新计时，避免任务重叠或追赶执行。
                 enabled, interval = _backup_policy()