diff --git a/seahub/templates/js/lib-op-popups.html b/seahub/templates/js/lib-op-popups.html
index e337c8c210..ab53a05626 100644
--- a/seahub/templates/js/lib-op-popups.html
+++ b/seahub/templates/js/lib-op-popups.html
@@ -112,6 +112,7 @@
         <div>
             <h3><%= title %></h3>
             <p>{% trans "A file with the same name already exists in this folder." %}<br />{% trans "Replacing it will overwrite its content." %}</p>
+            <p class="error hide"></p>
             <button class="yes btn">{% trans "Replace" %}</button>
             <button class="no btn" style="margin-left:5px;">{% trans "Don't replace" %}</button>
             <button class="simplemodal-close btn">{% trans "Cancel" %}</button>
diff --git a/static/scripts/app/views/fileupload.js b/static/scripts/app/views/fileupload.js
index 216f4425fd..de2c91f333 100644
--- a/static/scripts/app/views/fileupload.js
+++ b/static/scripts/app/views/fileupload.js
@@ -214,8 +214,14 @@ define([
                     });
                     $('#simplemodal-container').css({'height':'auto'});
                     $('.yes', confirm_popup).click(function() {
-                        file.choose_to_update = true;
-                        $.modal.close();
+                        var selected_file = dirents.findWhere({'obj_name': file.name});
+                        if (selected_file.get('is_locked')) {
+                            $('.error', confirm_popup).html(gettext("File is locked")).removeClass('hide');
+                            Common.disableButton($(this));
+                        } else {
+                            file.choose_to_update = true;
+                            $.modal.close();
+                        }
                     });
                     $('.no', confirm_popup).click(function() {
                         file.choose_to_upload = true;