diff --git a/src/modules/admin-dashboard/admin-dashboard.service.ts b/src/modules/admin-dashboard/admin-dashboard.service.ts
index f0acec6..80bd4e7 100644
--- a/src/modules/admin-dashboard/admin-dashboard.service.ts
+++ b/src/modules/admin-dashboard/admin-dashboard.service.ts
@@ -30,7 +30,7 @@ export class AdminDashboardService {
       safe(() => this.prisma.knowledgeBase.count({ where: { createdAt: { gte: today, lt: tomorrow }, deletedAt: null } }), 0),
       safe(() => this.prisma.aiUsageLog.count({ where: { createdAt: { gte: today, lt: tomorrow } } }), 0),
       safe(() => this.prisma.uploadedFile.count(), 0),
-      safe(() => this.prisma.uploadedFile.aggregate({ _sum: { sizeBytes: true } }), { _sum: { sizeBytes: 0 } }),
+      safe(() => this.prisma.uploadedFile.aggregate({ _sum: { sizeBytes: true } }), { _sum: { sizeBytes: BigInt(0) } }),
     ]);
 
     const userTrend = await this.getUserTrend(30);