diff --git a/apps/mobile/lib/features/uploads/enqueue.dart b/apps/mobile/lib/features/uploads/enqueue.dart
index 029b01c..62f36e3 100644
--- a/apps/mobile/lib/features/uploads/enqueue.dart
+++ b/apps/mobile/lib/features/uploads/enqueue.dart
@@ -149,16 +149,17 @@ Future<EnqueueResult> enqueueForUpload(
       .where((path) => !skipSet.contains(path))
       .toList();
 
-  var enqueued = 0;
-  for (final path in effective) {
-    final task = await preparer.prepare(
-      accountId: accountId,
-      albumId: albumId,
-      categoryId: categoryId,
-      sourcePath: path,
-    );
-    if (task.state == UploadTaskState.queued) enqueued++;
-  }
+  final results = await Future.wait(
+    effective.map((path) => preparer.prepare(
+          accountId: accountId,
+          albumId: albumId,
+          categoryId: categoryId,
+          sourcePath: path,
+        )),
+  );
+  final enqueued = results
+      .where((task) => task.state == UploadTaskState.queued)
+      .length;
 
   return EnqueueResult(
     enqueued: enqueued,
diff --git a/apps/mobile/test/features/uploads/preparer_test.dart b/apps/mobile/test/features/uploads/preparer_test.dart
index 8d6fcc0..7a417a5 100644
--- a/apps/mobile/test/features/uploads/preparer_test.dart
+++ b/apps/mobile/test/features/uploads/preparer_test.dart
@@ -275,6 +275,46 @@ void main() {
       expect(tasks.map((t) => t.state), everyElement(UploadTaskState.queued));
       expect(peakOf(), 1, reason: '并发 1 时任意时刻在途 prepare 至多 1（串行）');
     });
+
+    test('maxConcurrentPrepares<1 钳位为 1（0 不死锁、串行等价）', () async {
+      final (p, peakOf) = probePreparer(0);
+      final srcs = [
+        for (var i = 0; i < 3; i++)
+          sourceFile('clamp-$i.jpg', _jpgBytes + [i]),
+      ];
+      final tasks = await Future.wait([
+        for (final src in srcs)
+          p.prepare(accountId: 'alice', albumId: 'alb-1', sourcePath: src.path),
+      ]);
+      expect(tasks.map((t) => t.state), everyElement(UploadTaskState.queued));
+      expect(peakOf(), 1, reason: '运行时 <1 按 1 处理：峰值 1（不死锁、不并行）');
+    });
+
+    test('失败与抛错操作都释放并发名额（cap=1 后续 prepare 不被卡死）', () async {
+      final p = preparer(maxConcurrentPrepares: 1);
+      final src = sourceFile('after-error.jpg', _jpgBytes);
+
+      // 业务失败：源不存在 → preparationFailed（正常返回、不抛）。
+      final failed = await p.prepare(
+        accountId: 'alice',
+        albumId: 'alb-1',
+        sourcePath: '${sourceDir.path}/missing.jpg',
+      );
+      expect(failed.state, UploadTaskState.preparationFailed);
+
+      // 真错误：retry 不存在的任务 → StateError 穿过 _runBounded——
+      // 钉死 whenComplete 语义（若改成 then，此处名额泄漏）。
+      await expectLater(
+        p.retry(accountId: 'alice', taskId: 'no-such-task', sourcePath: src.path),
+        throwsA(isA<StateError>()),
+      );
+
+      // 名额已释放：后续 prepare 正常完成（泄漏则卡死，超时快速失败）。
+      final task = await p
+          .prepare(accountId: 'alice', albumId: 'alb-1', sourcePath: src.path)
+          .timeout(const Duration(seconds: 5));
+      expect(task.state, UploadTaskState.queued);
+    });
   });
 
   group('串行回归（maxConcurrentPrepares=1 等价旧全局串行队列）', () {