diff --git a/src/controllers/api/loginController.ts b/src/controllers/api/loginController.ts
index 6f81fbaa..51d3815f 100644
--- a/src/controllers/api/loginController.ts
+++ b/src/controllers/api/loginController.ts
@@ -6,7 +6,7 @@ import buildConfig from "@/static/data/buildConfig.json";
 
 import { toLoginRequest } from "@/src/helpers/loginHelpers";
 import { Account } from "@/src/models/loginModel";
-import { createAccount, isCorrectPassword } from "@/src/services/loginService";
+import { createAccount, isCorrectPassword, isNameTaken } from "@/src/services/loginService";
 import { IDatabaseAccountJson, ILoginResponse } from "@/src/types/loginTypes";
 import { DTLS, groups, HUB, platformCDNs } from "@/static/fixed_responses/login_static";
 import { logger } from "@/src/utils/logger";
@@ -26,10 +26,19 @@ export const loginController: RequestHandler = async (request, response) => {
 
     if (!account && config.autoCreateAccount && loginRequest.ClientType != "webui") {
         try {
+            const nameFromEmail = loginRequest.email.substring(0, loginRequest.email.indexOf("@"));
+            let name = nameFromEmail;
+            if (await isNameTaken(name)) {
+                let suffix = 0;
+                do {
+                    ++suffix;
+                    name = nameFromEmail + suffix;
+                } while (await isNameTaken(name));
+            }
             const newAccount = await createAccount({
                 email: loginRequest.email,
                 password: loginRequest.password,
-                DisplayName: loginRequest.email.substring(0, loginRequest.email.indexOf("@")),
+                DisplayName: name,
                 CountryCode: loginRequest.lang.toUpperCase(),
                 ClientType: loginRequest.ClientType,
                 CrossPlatformAllowed: true,
diff --git a/src/controllers/custom/createAccountController.ts b/src/controllers/custom/createAccountController.ts
index 723b31c9..bac12508 100644
--- a/src/controllers/custom/createAccountController.ts
+++ b/src/controllers/custom/createAccountController.ts
@@ -1,14 +1,16 @@
 import { toCreateAccount, toDatabaseAccount } from "@/src/helpers/customHelpers/customHelpers";
-import { createAccount } from "@/src/services/loginService";
+import { createAccount, isNameTaken } from "@/src/services/loginService";
 import { RequestHandler } from "express";
 
 const createAccountController: RequestHandler = async (req, res) => {
     const createAccountData = toCreateAccount(req.body);
-    const databaseAccount = toDatabaseAccount(createAccountData);
-
-    const account = await createAccount(databaseAccount);
-
-    res.json(account);
+    if (await isNameTaken(createAccountData.DisplayName)) {
+        res.status(409).json("Name already in use");
+    } else {
+        const databaseAccount = toDatabaseAccount(createAccountData);
+        const account = await createAccount(databaseAccount);
+        res.json(account);
+    }
 };
 
 export { createAccountController };
diff --git a/src/controllers/custom/renameAccountController.ts b/src/controllers/custom/renameAccountController.ts
index 1631cc02..c5b733e8 100644
--- a/src/controllers/custom/renameAccountController.ts
+++ b/src/controllers/custom/renameAccountController.ts
@@ -1,12 +1,16 @@
 import { RequestHandler } from "express";
-import { getAccountForRequest } from "@/src/services/loginService";
+import { getAccountForRequest, isNameTaken } from "@/src/services/loginService";
 
 export const renameAccountController: RequestHandler = async (req, res) => {
     const account = await getAccountForRequest(req);
     if (typeof req.query.newname == "string") {
-        account.DisplayName = req.query.newname;
-        await account.save();
-        res.end();
+        if (await isNameTaken(req.query.newname)) {
+            res.status(409).json("Name already in use");
+        } else {
+            account.DisplayName = req.query.newname;
+            await account.save();
+            res.end();
+        }
     } else {
         res.status(400).end();
     }
diff --git a/src/services/loginService.ts b/src/services/loginService.ts
index c251409d..0d49bb27 100644
--- a/src/services/loginService.ts
+++ b/src/services/loginService.ts
@@ -12,6 +12,10 @@ export const isCorrectPassword = (requestPassword: string, databasePassword: str
     return requestPassword === databasePassword;
 };
 
+export const isNameTaken = async (name: string): Promise<boolean> => {
+    return !!(await Account.findOne({ DisplayName: name }));
+};
+
 export const createAccount = async (accountData: IDatabaseAccount): Promise<IDatabaseAccountJson> => {
     const account = new Account(accountData);
     try {