diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1332da69f..d184a0b39 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -48,6 +48,8 @@
 - Fix: エンドポイント`notes/translate`のエラーを改善
 - Fix: CleanRemoteFilesProcessorService report progress from 100% (#13632)
 - Fix: 一部の音声ファイルが映像ファイルとして扱われる問題を修正
+- Fix: 登録にメール認証が必須になっている場合、登録されているメールアドレスを削除できないように  
+  (Cherry-picked from https://github.com/MisskeyIO/misskey/pull/606)
 
 ## 2024.3.1
 
diff --git a/packages/backend/src/server/api/endpoints/i/update-email.ts b/packages/backend/src/server/api/endpoints/i/update-email.ts
index 386827869..eea657ebb 100644
--- a/packages/backend/src/server/api/endpoints/i/update-email.ts
+++ b/packages/backend/src/server/api/endpoints/i/update-email.ts
@@ -15,6 +15,7 @@ import { DI } from '@/di-symbols.js';
 import { GlobalEventService } from '@/core/GlobalEventService.js';
 import { L_CHARS, secureRndstr } from '@/misc/secure-rndstr.js';
 import { UserAuthService } from '@/core/UserAuthService.js';
+import { MetaService } from '@/core/MetaService.js';
 import { ApiError } from '../../error.js';
 
 export const meta = {
@@ -39,6 +40,12 @@ export const meta = {
 			code: 'UNAVAILABLE',
 			id: 'a2defefb-f220-8849-0af6-17f816099323',
 		},
+
+		emailRequired: {
+			message: 'Email address is required.',
+			code: 'EMAIL_REQUIRED',
+			id: '324c7a88-59f2-492f-903f-89134f93e47e',
+		},
 	},
 
 	res: {
@@ -66,6 +73,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		@Inject(DI.userProfilesRepository)
 		private userProfilesRepository: UserProfilesRepository,
 
+		private metaService: MetaService,
 		private userEntityService: UserEntityService,
 		private emailService: EmailService,
 		private userAuthService: UserAuthService,
@@ -97,6 +105,8 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				if (!res.available) {
 					throw new ApiError(meta.errors.unavailable);
 				}
+			} else if ((await this.metaService.fetch()).emailRequiredForSignup) {
+				throw new ApiError(meta.errors.emailRequired);
 			}
 
 			await this.userProfilesRepository.update(me.id, {