diff --git a/src/main/scala/app/AccountController.scala b/src/main/scala/app/AccountController.scala
index 90bbc70..ab77092 100644
--- a/src/main/scala/app/AccountController.scala
+++ b/src/main/scala/app/AccountController.scala
@@ -16,7 +16,7 @@
   case class AccountEditForm(password: Option[String], mailAddress: String, url: Option[String])
 
   val newForm = mapping(
-    "userName"    -> trim(label("User name"    , text(required, maxlength(100)))),
+    "userName"    -> trim(label("User name"    , text(required, maxlength(100), identifier, unique))),
     "password"    -> trim(label("Password"     , text(required, maxlength(20)))),
     "mailAddress" -> trim(label("Mail Address" , text(required, maxlength(100)))),
     "url"         -> trim(label("URL"          , optional(text(maxlength(200)))))
@@ -66,4 +66,10 @@
       redirect("/signin")
     } else NotFound
   }
+
+  private def unique: Constraint = new Constraint(){
+    def validate(name: String, value: String): Option[String] =
+      getAccountByUserName(value).map { _ => "User already exists." }
+  }
+
 }
diff --git a/src/main/twirl/account/useredit.scala.html b/src/main/twirl/account/useredit.scala.html
index 2c97247..4b8bf47 100644
--- a/src/main/twirl/account/useredit.scala.html
+++ b/src/main/twirl/account/useredit.scala.html
@@ -18,7 +18,7 @@
     <fieldset>
       <label for="password"><strong>Password</strong>
         @if(account.nonEmpty){
-          (Input if you want to change password)
+          (Input to change password)
         }
       </label>
       <input type="password" name="password" id="password" value=""/>
diff --git a/src/main/twirl/admin/useredit.scala.html b/src/main/twirl/admin/useredit.scala.html
index c8aa1d7..fd75328 100644
--- a/src/main/twirl/admin/useredit.scala.html
+++ b/src/main/twirl/admin/useredit.scala.html
@@ -9,8 +9,12 @@
         <span id="error-userName" class="error"></span>
       </fieldset>
       <fieldset>
-        <label for="password"><strong>Password</strong></label>
-        <input type="password" name="password" id="password" value="@account.map(_.password)"/>
+        <label for="password"><strong>Password</strong>
+          @if(account.isDefined){
+            (Input to change password)
+          }
+        </label>
+        <input type="password" name="password" id="password" value=""/>
         <span id="error-password" class="error"></span>
       </fieldset>
       <fieldset>