diff --git a/client/lib/dialog.dart b/client/lib/dialog.dart
index 6486063..b6fc7b5 100644
--- a/client/lib/dialog.dart
+++ b/client/lib/dialog.dart
@@ -104,13 +104,13 @@ class _AppConfigDialogState extends State<AppConfigDialog> {
           Row(
             mainAxisAlignment: MainAxisAlignment.spaceEvenly,
             children: [
-              FilledButton(
+              ElevatedButton(
                 onPressed: () {
                   Navigator.of(context).pop();
                 },
                 child: Text('取消'),
               ),
-              ElevatedButton(
+              FilledButton(
                 onPressed: () {
                   var client = clientCtl.text.trim();
                   var server = serverCtl.text.trim();
@@ -223,12 +223,10 @@ class _AddSyncItemDialogState extends State<AddSyncItemDialog> {
             children: [
               IconButton(
                 onPressed: () {
-                  FilePicker.pickFiles(
-                    allowMultiple: false,
-                  ).then(
+                  FilePicker.pickFile().then(
                     (res) {
-                      if (res?.files.firstOrNull?.path?.isNotEmpty == true) {
-                        pathCtl.text = res!.files.first.path!;
+                      if (res?.xFile.path?.isNotEmpty == true) {
+                        pathCtl.text = res!.xFile.path!;
                       }
                     },
                   );
@@ -253,13 +251,13 @@ class _AddSyncItemDialogState extends State<AddSyncItemDialog> {
           Row(
             mainAxisAlignment: MainAxisAlignment.spaceEvenly,
             children: [
-              FilledButton(
+              ElevatedButton(
                 onPressed: () {
                   Navigator.of(context).pop();
                 },
                 child: Text('取消'),
               ),
-              ElevatedButton(
+              FilledButton(
                 onPressed: () {
                   var name = nameCtl.text.trim();
                   var path = pathCtl.text.trim();
@@ -284,3 +282,69 @@ class _AddSyncItemDialogState extends State<AddSyncItemDialog> {
     );
   }
 }
+
+class UploadConfirmDialog extends StatelessWidget {
+  const UploadConfirmDialog({super.key});
+
+  static Future<bool?> show(BuildContext context, [SyncItemConfig? config]) {
+    return showDialog(
+      context: context,
+      builder: (context) => Dialog(
+        child: UploadConfirmDialog(),
+      ),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: 400,
+      height: 200,
+      padding: EdgeInsets.all(16),
+      decoration: BoxDecoration(
+        borderRadius: BorderRadius.circular(16),
+        color: Colors.white,
+        boxShadow: [
+          BoxShadow(
+            color: Colors.black26,
+            offset: Offset(4, 4),
+            spreadRadius: 8,
+            blurRadius: 16,
+          ),
+        ],
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.center,
+        children: [
+          Text(
+            '确认下载并覆盖本地数据？',
+            style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
+          ),
+          SizedBox(height: 26),
+          Text(
+            '本地资源修改时间似乎晚于云端\n确认覆盖可能造成数据丢失！',
+            textAlign: TextAlign.center,
+          ),
+          const Spacer(),
+          Row(
+            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+            children: [
+              ElevatedButton(
+                onPressed: () {
+                  Navigator.of(context).pop(false);
+                },
+                child: Text('取消'),
+              ),
+              FilledButton(
+                onPressed: () {
+                  Navigator.of(context).pop(true);
+                },
+                child: Text('确认'),
+              ),
+            ],
+          ),
+        ],
+      ),
+    );
+  }
+}
diff --git a/client/lib/main.dart b/client/lib/main.dart
index f9d6d11..690ea95 100644
--- a/client/lib/main.dart
+++ b/client/lib/main.dart
@@ -105,6 +105,7 @@ class _MyHomePageState extends State<MyHomePage> {
           IconButton(
             onPressed: () {
               loadCloudArchives();
+              loadLocalStatus();
             },
             icon: Icon(Icons.refresh_outlined),
           ),
@@ -210,9 +211,16 @@ class _MyHomePageState extends State<MyHomePage> {
                                       return InkWell(
                                         onTap: cloudModifiedTimeTs == null
                                             ? null
-                                            : () {
+                                            : () async {
                                                 if (syncItemConfig != null) {
-                                                  download(context, syncItemConfig, cloudArchives.sorted.first);
+                                                  if (cloudModifiedTimeTs != null &&
+                                                      localModifiedTime != null &&
+                                                      localModifiedTime.millisecondsSinceEpoch > cloudModifiedTimeTs) {
+                                                    if (await UploadConfirmDialog.show(context) != true) return;
+                                                  }
+                                                  if (context.mounted) {
+                                                    download(context, syncItemConfig, cloudArchives.sorted.first);
+                                                  }
                                                 }
                                               },
                                         onLongPress: cloudModifiedTimeTs == null
diff --git a/client/lib/utils.dart b/client/lib/utils.dart
index a007b10..f7da7dd 100644
--- a/client/lib/utils.dart
+++ b/client/lib/utils.dart
@@ -4,6 +4,7 @@ import 'package:archive/archive_io.dart';
 import 'package:cloud_archiver/config.dart';
 import 'package:cloud_archiver/state.dart';
 import 'package:filesize/filesize.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:path/path.dart';
 import 'package:path_provider/path_provider.dart';
@@ -24,7 +25,7 @@ String totalSize() {
 Future<bool> connect(String server, String user, String auth) async {
   var client = dav.newClient(
     server,
-    debug: true,
+    debug: kDebugMode,
     user: user,
     password: auth,
   );
diff --git a/server/.gitignore b/server/.gitignore
index e4ce6a1..0325afb 100644
--- a/server/.gitignore
+++ b/server/.gitignore
@@ -1,3 +1,4 @@
 # https://dart.dev/tools/private-files
 # Created by `dart pub`
 .dart_tool/
+repo/
diff --git a/server/bin/server.dart b/server/bin/server.dart
index dd91087..8c20c86 100644
--- a/server/bin/server.dart
+++ b/server/bin/server.dart
@@ -2,6 +2,7 @@ import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:file/local.dart';
+import 'package:shelf/shelf.dart';
 import 'package:shelf/shelf_io.dart';
 import 'package:shelf_dav/shelf_dav.dart';
 
@@ -24,6 +25,7 @@ void main(List<String> args) async {
   if (!rootDir.existsSync()) {
     rootDir.createSync(recursive: true);
   }
+  var user = argResults.option('user')!;
   final config = DAVConfig(
     root: rootDir,
     prefix: '/dav',
@@ -33,7 +35,7 @@ void main(List<String> args) async {
     readOnly: false,
     propertyStorageType: PropertyStorageType.file,
     authenticationProvider: BasicAuthenticationProvider.plaintext(
-      users: {argResults.option('user')!: argResults.option('auth')!},
+      users: {user: argResults.option('auth')!},
     ),
   );
 
@@ -42,6 +44,39 @@ void main(List<String> args) async {
   final ip = InternetAddress.anyIPv4;
 
   final port = int.parse(argResults.option('port') ?? '8800');
-  final server = await serve(dav.handler, ip, port);
+  final server = await serve(
+    (request) {
+      if (request.method == 'GET' && request.url.path == 'info/$user') {
+        return getInfo(rootDir);
+      }
+
+      return dav.handler.call(request);
+    },
+    ip,
+    port,
+  );
   print('WebDAV server listening on port ${server.port}');
 }
+
+Response getInfo(Directory dir) {
+  var du = Process.runSync('du', [
+    '-h',
+    '--time',
+    dir.absolute.path,
+  ]).stdout.toString();
+  var result = <String>[];
+  for (var line in du.split('\n')) {
+    var parts = line.split(dir.absolute.path);
+    if (parts.length == 2) {
+      if (parts.last.trim().isEmpty) {
+        result.insert(0, '${parts.first}总占用\n');
+      } else {
+        result.add('${parts.first}${Uri.decodeComponent(parts.last)}');
+      }
+    }
+  }
+  return Response.ok(
+    result.join('\n'),
+    headers: {'content-type': 'text/plain'},
+  );
+}