diff --git a/packages/backend-core/src/errors/errors.ts b/packages/backend-core/src/errors/errors.ts
index 54ca8456ab..0a632d7551 100644
--- a/packages/backend-core/src/errors/errors.ts
+++ b/packages/backend-core/src/errors/errors.ts
@@ -97,3 +97,11 @@ export class InvalidAPIKeyError extends BudibaseError {
     )
   }
 }
+
+// USERS
+
+export class EmailUnavailableError extends Error {
+  constructor(email: string) {
+    super(`Email already taken: '${email}'`)
+  }
+}
diff --git a/packages/worker/src/sdk/users/users.ts b/packages/worker/src/sdk/users/users.ts
index f05c6b98d2..2150654ae9 100644
--- a/packages/worker/src/sdk/users/users.ts
+++ b/packages/worker/src/sdk/users/users.ts
@@ -16,6 +16,7 @@ import {
   ViewName,
   env as coreEnv,
   context,
+  EmailUnavailableError,
 } from "@budibase/backend-core"
 import {
   AccountMetadata,
@@ -158,7 +159,7 @@ const validateUniqueUser = async (email: string, tenantId: string) => {
   if (env.MULTI_TENANCY) {
     const tenantUser = await getPlatformUser(email)
     if (tenantUser != null && tenantUser.tenantId !== tenantId) {
-      throw `Unavailable`
+      throw new EmailUnavailableError(email)
     }
   }
 
@@ -166,7 +167,7 @@ const validateUniqueUser = async (email: string, tenantId: string) => {
   if (!env.SELF_HOSTED && !env.DISABLE_ACCOUNT_PORTAL) {
     const account = await accounts.getAccount(email)
     if (account && account.verified && account.tenantId !== tenantId) {
-      throw `Unavailable`
+      throw new EmailUnavailableError(email)
     }
   }
 }
@@ -235,7 +236,7 @@ export const save = async (
     // no id was specified - load from email instead
     dbUser = await usersCore.getGlobalUserByEmail(email)
     if (dbUser && dbUser._id !== _id) {
-      throw `Unavailable`
+      throw new EmailUnavailableError(email)
     }
   }