diff --git a/locales/en-US.yml b/locales/en-US.yml
index 084008868..6ba9cdaea 100644
--- a/locales/en-US.yml
+++ b/locales/en-US.yml
@@ -847,6 +847,7 @@ cropImage: "Crop image"
 cropImageAsk: "Do you want to crop this image?"
 recentNHours: "Last {n} hours"
 recentNDays: "Last {n} days"
+isSystemAccount: "An account created and automatically operated by the system."
 _emailUnavailable:
   used: "This email address is already being used"
   format: "The format of this email address is invalid"
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 594727540..d7fe4dcb2 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -854,6 +854,7 @@ recommended: "推奨"
 check: "チェック"
 recentNHours: "直近{n}時間"
 recentNDays: "直近{n}日"
+isSystemAccount: "システムにより自動で作成・管理されているアカウントです。"
 
 _emailUnavailable:
   used: "既に使用されています"
diff --git a/packages/client/src/pages/admin-file.vue b/packages/client/src/pages/admin-file.vue
index 67ebdd467..402e9502d 100644
--- a/packages/client/src/pages/admin-file.vue
+++ b/packages/client/src/pages/admin-file.vue
@@ -28,7 +28,7 @@
 					<template #value><span class="_monospace"><MkTime :time="file.createdAt" mode="detail" style="display: block;"/></span></template>
 				</MkKeyValue>
 			</div>
-			<MkA class="user" :to="`/user-info/${file.user.id}`">
+			<MkA v-if="file.user" class="user" :to="`/user-info/${file.user.id}`">
 				<MkUserCardMini :user="file.user"/>
 			</MkA>
 			<div class="_formBlock">
diff --git a/packages/client/src/pages/user-info.vue b/packages/client/src/pages/user-info.vue
index b4c4aedfc..86c1be8d0 100644
--- a/packages/client/src/pages/user-info.vue
+++ b/packages/client/src/pages/user-info.vue
@@ -12,6 +12,8 @@
 					</div>
 				</div>
 
+				<MkInfo v-if="user.username.includes('.')" class="_formBlock">{{ i18n.ts.isSystemAccount }}</MkInfo>
+
 				<div v-if="user.url" class="_formLinksGrid _formBlock">
 					<FormLink :to="userPage(user)">Profile</FormLink>
 					<FormLink :to="user.url" :external="true">Profile (remote)</FormLink>