diff --git a/src/main/services/FileStorage.ts b/src/main/services/FileStorage.ts
index ce25937f..06b64744 100644
--- a/src/main/services/FileStorage.ts
+++ b/src/main/services/FileStorage.ts
@@ -174,7 +174,7 @@ class FileStorage {
       origin_name,
       name: uuid + ext,
       path: destPath,
-      created_at: stats.birthtime,
+      created_at: stats.birthtime.toISOString(),
       size: stats.size,
       ext: ext,
       type: fileType,
@@ -198,7 +198,7 @@ class FileStorage {
       origin_name: path.basename(filePath),
       name: path.basename(filePath),
       path: filePath,
-      created_at: stats.birthtime,
+      created_at: stats.birthtime.toISOString(),
       size: stats.size,
       ext: ext,
       type: fileType,
@@ -416,7 +416,7 @@ class FileStorage {
         origin_name: filename,
         name: uuid + ext,
         path: destPath,
-        created_at: stats.birthtime,
+        created_at: stats.birthtime.toISOString(),
         size: stats.size,
         ext: ext,
         type: fileType,
diff --git a/src/renderer/src/databases/upgrades.ts b/src/renderer/src/databases/upgrades.ts
index e6607d5f..9149c25e 100644
--- a/src/renderer/src/databases/upgrades.ts
+++ b/src/renderer/src/databases/upgrades.ts
@@ -2,6 +2,14 @@ import { Transaction } from 'dexie'
 
 export async function upgradeToV5(tx: Transaction): Promise<void> {
   const topics = await tx.table('topics').toArray()
+  const files = await tx.table('files').toArray()
+
+  for (const file of files) {
+    if (file.created_at instanceof Date) {
+      file.created_at = file.created_at.toISOString()
+      await tx.table('files').put(file)
+    }
+  }
 
   for (const topic of topics) {
     let hasChanges = false
diff --git a/src/renderer/src/types/index.ts b/src/renderer/src/types/index.ts
index fa9011bc..7b4c022c 100644
--- a/src/renderer/src/types/index.ts
+++ b/src/renderer/src/types/index.ts
@@ -168,7 +168,7 @@ export interface FileType {
   size: number
   ext: string
   type: FileTypes
-  created_at: Date
+  created_at: string
   count: number
   tokens?: number
 }