diff --git a/program/js/app.js b/program/js/app.js
index 5f8d125f6..2cbd27b81 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -2652,7 +2652,7 @@ function rcube_webmail()
 
       if (name.indexOf(this.env.delimiter)>=0)
         {
-        alert(this.get_label('forbiddencharacter'));
+        alert(this.get_label('forbiddencharacter')+' ('+this.env.delimiter+')');
         return false;
         }
 
@@ -2724,15 +2724,15 @@ function rcube_webmail()
       var newname = this.name_input ? this.name_input.value : null;
       if (this.edit_folder && newname)
         {
-	if (newname.indexOf(this.env.delimiter)>=0)
+        if (newname.indexOf(this.env.delimiter)>=0)
           {
-          alert(this.get_label('forbiddencharacter'));
+          alert(this.get_label('forbiddencharacter')+' ('+this.env.delimiter+')');
           return false;
           }
 
         if (this.name_input.__parent)
           newname = this.name_input.__parent + this.env.delimiter + newname;
-	
+
         this.http_post('rename-folder', '_folder_oldname='+urlencode(this.env.subscriptionrows[this.edit_folder][0])+'&_folder_newname='+urlencode(newname));
         }
       }
diff --git a/program/localization/de_CH/messages.inc b/program/localization/de_CH/messages.inc
index fd6a266cd..573288aa7 100644
--- a/program/localization/de_CH/messages.inc
+++ b/program/localization/de_CH/messages.inc
@@ -81,5 +81,6 @@ $messages['errorsendingreceipt'] = 'Bestätigung konnte nicht gesendet werden';
 
 $messages['nodeletelastidentity'] = 'Sie können diesen Absender nicht löschen';
 $messages['addsubfolderhint'] = 'Wird als Unterdornder des aktuell selektieren Ordners erstellt';
+$messages['forbiddencharacter'] = 'Der Ordnername enthält ein ungültiges Zeichen';
 
 ?>
\ No newline at end of file
diff --git a/program/localization/de_DE/messages.inc b/program/localization/de_DE/messages.inc
index 16eefe1a4..5cb1f0c64 100644
--- a/program/localization/de_DE/messages.inc
+++ b/program/localization/de_DE/messages.inc
@@ -78,5 +78,6 @@ $messages['receiptsent'] = 'Lesebestätigung erfolgreich gesendet';
 $messages['errorsendingreceipt'] = 'Bestätigung konnte nicht gesendet werden';
 $messages['nodeletelastidentity'] = 'Diese Identität kann nicht gelöscht werden, da dies die letzte ist.';
 $messages['addsubfolderhint'] = 'Wird als Unterordner des aktuell selektieren Ordners erstellt';
+$messages['forbiddencharacter'] = 'Der Ordnername enthält ein ungültiges Zeichen';
 
 ?>
\ No newline at end of file
diff --git a/program/localization/en_US/messages.inc b/program/localization/en_US/messages.inc
index 108b3565f..d7b3f0380 100644
--- a/program/localization/en_US/messages.inc
+++ b/program/localization/en_US/messages.inc
@@ -78,6 +78,6 @@ $messages['receiptsent'] = 'Successfully sent a read receipt';
 $messages['errorsendingreceipt'] = 'Could not send the receipt';
 $messages['nodeletelastidentity'] = 'You cannot delete this identity, it\'s your last one.';
 $messages['addsubfolderhint'] = 'This folder will be created as subfolder of the currently selected one';
-$messages['forbiddencharacter'] = 'Folder name contains forbidden character';
+$messages['forbiddencharacter'] = 'Folder name contains a forbidden character';
 
 ?>
\ No newline at end of file