diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/auth/userpass/UserPassSignInDialog.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/auth/userpass/UserPassSignInDialog.java
index 6dd0cd5..c4709a5 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/auth/userpass/UserPassSignInDialog.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/auth/userpass/UserPassSignInDialog.java
@@ -227,7 +227,7 @@
       @Override
       public void onFailure(final Throwable caught) {
         super.onFailure(caught);
-        enable(false);
+        enable(true);
       }
     });
   }
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/ldap/UserPassAuthServiceImpl.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/ldap/UserPassAuthServiceImpl.java
index a59d013..e4577c1 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/ldap/UserPassAuthServiceImpl.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/ldap/UserPassAuthServiceImpl.java
@@ -19,6 +19,7 @@
 import com.google.gerrit.httpd.WebSession;
 import com.google.gerrit.server.account.AccountException;
 import com.google.gerrit.server.account.AccountManager;
+import com.google.gerrit.server.account.AccountUserNameException;
 import com.google.gerrit.server.account.AuthRequest;
 import com.google.gerrit.server.account.AuthResult;
 import com.google.gwt.user.client.rpc.AsyncCallback;
@@ -55,6 +56,12 @@
     final AuthResult res;
     try {
       res = accountManager.authenticate(req);
+    } catch (AccountUserNameException e) {
+      // entered user name and password were correct, but user name could not be
+      // set for the newly created account and this is why the login fails,
+      // error screen with error message should be shown to the user
+      callback.onFailure(e);
+      return;
     } catch (AccountException e) {
       result.success = false;
       callback.onSuccess(result);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountManager.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountManager.java
index 83a5eed..5cb8f36 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountManager.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountManager.java
@@ -290,13 +290,18 @@
       try {
         changeUserNameFactory.create(db, user, who.getUserName()).call();
       } catch (NameAlreadyUsedException e) {
-        log.error("Cannot assign user name \"" + who.getUserName()
-            + "\" to account " + newId + "; name already in use.");
+        final String message =
+            "Cannot assign user name \"" + who.getUserName() + "\" to account "
+                + newId + "; name already in use.";
+        handleSettingUserNameFailure(db, account, extId, message, e, false);
       } catch (InvalidUserNameException e) {
-        log.error("Cannot assign user name \"" + who.getUserName()
-            + "\" to account " + newId + "; name does not conform.");
+        final String message =
+            "Cannot assign user name \"" + who.getUserName() + "\" to account "
+                + newId + "; name does not conform.";
+        handleSettingUserNameFailure(db, account, extId, message, e, false);
       } catch (OrmException e) {
-        log.error("Cannot assign user name", e);
+        final String message = "Cannot assign user name";
+        handleSettingUserNameFailure(db, account, extId, message, e, true);
       }
     }
 
@@ -305,6 +310,49 @@
     return new AuthResult(newId, extId.getKey(), true);
   }
 
+  /**
+   * This method handles an exception that occurred during the setting of the
+   * user name for a newly created account. If the realm does not allow the user
+   * to set a user name manually this method deletes the newly created account
+   * and throws an {@link AccountUserNameException}. In any case the error
+   * message is logged.
+   *
+   * @param db the database
+   * @param account the newly created account
+   * @param extId the newly created external id
+   * @param errorMessage the error message
+   * @param e the exception that occurred during the setting of the user name
+   *        for the new account
+   * @param logException flag that decides whether the exception should be
+   *        included into the log
+   * @throws AccountUserNameException thrown if the realm does not allow the
+   *         user to manually set the user name
+   * @throws OrmException thrown if cleaning the database failed
+   */
+  private void handleSettingUserNameFailure(final ReviewDb db,
+      final Account account, final AccountExternalId extId,
+      final String errorMessage, final Exception e, final boolean logException)
+      throws AccountUserNameException, OrmException {
+    if (logException) {
+      log.error(errorMessage, e);
+    } else {
+      log.error(errorMessage);
+    }
+    if (!realm.allowsEdit(Account.FieldName.USER_NAME)) {
+      // setting the given user name has failed, but the realm does not
+      // allow the user to manually set a user name,
+      // this means we would end with an account without user name
+      // (without 'username:<USERNAME>' entry in
+      // account_external_ids table),
+      // such an account cannot be used for uploading changes,
+      // this is why the best we can do here is to fail early and cleanup
+      // the database
+      db.accounts().delete(Collections.singleton(account));
+      db.accountExternalIds().delete(Collections.singleton(extId));
+      throw new AccountUserNameException(errorMessage, e);
+    }
+  }
+
   private static AccountExternalId createId(final Account.Id newId,
       final AuthRequest who) {
     final String ext = who.getExternalId();
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountUserNameException.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountUserNameException.java
new file mode 100644
index 0000000..1cf8be8
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountUserNameException.java
@@ -0,0 +1,28 @@
+// Copyright (C) 2010 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.account;
+
+/**
+ * Thrown by {@link AccountManager} if the user name for a newly created account
+ * could not be set and the realm does not allow the user to set a user name
+ * manually.
+ */
+public class AccountUserNameException extends AccountException {
+  private static final long serialVersionUID = 1L;
+
+  public AccountUserNameException(final String message, final Throwable why) {
+    super(message, why);
+  }
+}