diff --git a/plugins/logger/package.json b/plugins/logger/package.json
index a99715bb..65b4e64d 100644
--- a/plugins/logger/package.json
+++ b/plugins/logger/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@koishijs/plugin-logger",
   "description": "Dump log files for Koishi",
-  "version": "2.6.7",
+  "version": "2.6.8",
   "main": "lib/index.js",
   "typings": "lib/index.d.ts",
   "files": [
diff --git a/plugins/logger/src/index.ts b/plugins/logger/src/index.ts
index 45ca313a..dafe5818 100644
--- a/plugins/logger/src/index.ts
+++ b/plugins/logger/src/index.ts
@@ -116,6 +116,7 @@ export async function apply(ctx: Context, config: Config) {
       if (writer.size >= config.maxSize) {
         writer.close()
         const index = Math.max(...files[date] ?? [0]) + 1
+        files[date] ??= []
         files[date].push(index)
         createFile(date, index)
       }