diff --git a/CHANGELOG.md b/CHANGELOG.md
index 37b18ad0cc..93d5d00f26 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,10 +4,11 @@
 -
 
 ### Client
+- サイズ制限を超過するファイルをアップロードしようとした際にエラーを出すように
 - Fix: アカウントがbotになっているときに二段階認証設定ダイアログの上にbotアカウントの注意書きが表示される問題を修正
 
 ### Server
--
+- ファイルがサイズの制限を超えてアップロードされた際にエラーを返さなかった問題を修正
 
 
 ## 2024.8.0
diff --git a/locales/index.d.ts b/locales/index.d.ts
index 75e1703b4a..9fd3441ab1 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -5068,6 +5068,10 @@ export interface Locale extends ILocale {
      * 作成したアンテナ
      */
     "createdAntennas": string;
+    /**
+     * これ以上このクリップにノートを追加できません。
+     */
+    "clipNoteLimitExceeded": string;
     "_delivery": {
         /**
          * 配信状態
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 98e3cbfa41..587b67d987 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -1263,6 +1263,7 @@ confirmWhenRevealingSensitiveMedia: "センシティブなメディアを表示
 sensitiveMediaRevealConfirm: "センシティブなメディアです。表示しますか？"
 createdLists: "作成したリスト"
 createdAntennas: "作成したアンテナ"
+clipNoteLimitExceeded: "これ以上このクリップにノートを追加できません。"
 
 _delivery:
   status: "配信状態"
diff --git a/packages/backend/src/config.ts b/packages/backend/src/config.ts
index 3e5a1e81cd..cff0194780 100644
--- a/packages/backend/src/config.ts
+++ b/packages/backend/src/config.ts
@@ -133,7 +133,7 @@ export type Config = {
 	proxySmtp: string | undefined;
 	proxyBypassHosts: string[] | undefined;
 	allowedPrivateNetworks: string[] | undefined;
-	maxFileSize: number | undefined;
+	maxFileSize: number;
 	clusterLimit: number | undefined;
 	id: string;
 	outgoingAddress: string | undefined;
@@ -250,7 +250,7 @@ export function loadConfig(): Config {
 		proxySmtp: config.proxySmtp,
 		proxyBypassHosts: config.proxyBypassHosts,
 		allowedPrivateNetworks: config.allowedPrivateNetworks,
-		maxFileSize: config.maxFileSize,
+		maxFileSize: config.maxFileSize ?? 262144000,
 		clusterLimit: config.clusterLimit,
 		outgoingAddress: config.outgoingAddress,
 		outgoingAddressFamily: config.outgoingAddressFamily,
diff --git a/packages/backend/src/core/DownloadService.ts b/packages/backend/src/core/DownloadService.ts
index 21ae798f9f..93f4a38246 100644
--- a/packages/backend/src/core/DownloadService.ts
+++ b/packages/backend/src/core/DownloadService.ts
@@ -42,7 +42,7 @@ export class DownloadService {
 
 		const timeout = 30 * 1000;
 		const operationTimeout = 60 * 1000;
-		const maxSize = this.config.maxFileSize ?? 262144000;
+		const maxSize = this.config.maxFileSize;
 
 		const urlObj = new URL(url);
 		let filename = urlObj.pathname.split('/').pop() ?? 'untitled';
diff --git a/packages/backend/src/core/entities/MetaEntityService.ts b/packages/backend/src/core/entities/MetaEntityService.ts
index 44ec0d6a7b..f4b1e302d0 100644
--- a/packages/backend/src/core/entities/MetaEntityService.ts
+++ b/packages/backend/src/core/entities/MetaEntityService.ts
@@ -129,6 +129,7 @@ export class MetaEntityService {
 			mediaProxy: this.config.mediaProxy,
 			enableUrlPreview: instance.urlPreviewEnabled,
 			noteSearchableScope: (this.config.meilisearch == null || this.config.meilisearch.scope !== 'local') ? 'global' : 'local',
+			maxFileSize: this.config.maxFileSize,
 		};
 
 		return packed;
diff --git a/packages/backend/src/models/json-schema/meta.ts b/packages/backend/src/models/json-schema/meta.ts
index 3bcf9cac92..99feeaa7d7 100644
--- a/packages/backend/src/models/json-schema/meta.ts
+++ b/packages/backend/src/models/json-schema/meta.ts
@@ -253,6 +253,10 @@ export const packedMetaLiteSchema = {
 			optional: false, nullable: false,
 			default: 'local',
 		},
+		maxFileSize: {
+			type: 'number',
+			optional: false, nullable: false,
+		},
 	},
 } as const;
 
diff --git a/packages/backend/src/server/api/ApiCallService.ts b/packages/backend/src/server/api/ApiCallService.ts
index 47f64f6609..f95c272757 100644
--- a/packages/backend/src/server/api/ApiCallService.ts
+++ b/packages/backend/src/server/api/ApiCallService.ts
@@ -199,9 +199,18 @@ export class ApiCallService implements OnApplicationShutdown {
 			return;
 		}
 
-		const [path] = await createTemp();
+		const [path, cleanup] = await createTemp();
 		await stream.pipeline(multipartData.file, fs.createWriteStream(path));
 
+		// ファイルサイズが制限を超えていた場合
+		// なお truncated はストリームを読み切ってからでないと機能しないため、stream.pipeline より後にある必要がある
+		if (multipartData.file.truncated) {
+			cleanup();
+			reply.code(413);
+			reply.send();
+			return;
+		}
+
 		const fields = {} as Record<string, unknown>;
 		for (const [k, v] of Object.entries(multipartData.fields)) {
 			fields[k] = typeof v === 'object' && 'value' in v ? v.value : undefined;
diff --git a/packages/backend/src/server/api/ApiServerService.ts b/packages/backend/src/server/api/ApiServerService.ts
index 4a5935f930..13cbdfc3be 100644
--- a/packages/backend/src/server/api/ApiServerService.ts
+++ b/packages/backend/src/server/api/ApiServerService.ts
@@ -49,7 +49,7 @@ export class ApiServerService {
 
 		fastify.register(multipart, {
 			limits: {
-				fileSize: this.config.maxFileSize ?? 262144000,
+				fileSize: this.config.maxFileSize,
 				files: 1,
 			},
 		});
diff --git a/packages/backend/src/server/web/boot.js b/packages/backend/src/server/web/boot.js
index 4275dc9527..5e52360456 100644
--- a/packages/backend/src/server/web/boot.js
+++ b/packages/backend/src/server/web/boot.js
@@ -176,10 +176,10 @@
 				<span class="button-label-big">Reload / リロード</span>
 			</button>
 			<p><b>The following actions may solve the problem. / 以下を行うと解決する可能性があります。</b></p>
-			<p>Clear the browser cache / ブラウザのキャッシュをクリアする</p>
 			<p>Update your os and browser / ブラウザおよびOSを最新バージョンに更新する</p>
 			<p>Disable an adblocker / アドブロッカーを無効にする</p>
-	 		<p>&#40;Tor Browser&#41; Set dom.webaudio.enabled to true / dom.webaudio.enabledをtrueに設定する</p>
+	 		<p>Clear the browser cache / ブラウザのキャッシュをクリアする</p>
+			<p>&#40;Tor Browser&#41; Set dom.webaudio.enabled to true / dom.webaudio.enabledをtrueに設定する</p>
 			<details style="color: #86b300;">
 				<summary>Other options / その他のオプション</summary>
 				<a href="/flush">
@@ -212,7 +212,7 @@
 		<summary>
 			<code>ERROR CODE: ${code}</code>
 		</summary>
-		<code>${JSON.stringify(details)}</code>`;
+		<code>${details.toString()} ${JSON.stringify(details)}</code>`;
 		errorsElement.appendChild(detailsElement);
 		addStyle(`
 		* {
diff --git a/packages/frontend/src/scripts/get-note-menu.ts b/packages/frontend/src/scripts/get-note-menu.ts
index 2563b0baf3..b5d7350a41 100644
--- a/packages/frontend/src/scripts/get-note-menu.ts
+++ b/packages/frontend/src/scripts/get-note-menu.ts
@@ -66,6 +66,11 @@ export async function getNoteClipMenu(props: {
 							});
 							if (props.currentClip?.id === clip.id) props.isDeleted.value = true;
 						}
+					} else if (err.id === 'f0dba960-ff73-4615-8df4-d6ac5d9dc118') {
+						os.alert({
+							type: 'error',
+							text: i18n.ts.clipNoteLimitExceeded,
+						});
 					} else {
 						os.alert({
 							type: 'error',
diff --git a/packages/frontend/src/scripts/upload.ts b/packages/frontend/src/scripts/upload.ts
index 3e947183c9..abb0e1e677 100644
--- a/packages/frontend/src/scripts/upload.ts
+++ b/packages/frontend/src/scripts/upload.ts
@@ -13,6 +13,7 @@ import { apiUrl } from '@/config.js';
 import { $i } from '@/account.js';
 import { alert } from '@/os.js';
 import { i18n } from '@/i18n.js';
+import { instance } from '@/instance.js';
 
 type Uploading = {
 	id: string;
@@ -39,6 +40,15 @@ export function uploadFile(
 
 	if (folder && typeof folder === 'object') folder = folder.id;
 
+	if (file.size > instance.maxFileSize) {
+		alert({
+			type: 'error',
+			title: i18n.ts.failedToUpload,
+			text: i18n.ts.cannotUploadBecauseExceedsFileSizeLimit,
+		});
+		return Promise.reject();
+	}
+
 	return new Promise((resolve, reject) => {
 		const id = uuid();
 
diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index 6d2f787767..0c50825203 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -4947,6 +4947,7 @@ export type components = {
        * @enum {string}
        */
       noteSearchableScope: 'local' | 'global';
+      maxFileSize: number;
     };
     MetaDetailedOnly: {
       features?: {