diff --git a/addons/project_gtd/project_gtd.py b/addons/project_gtd/project_gtd.py
index bb61617c9f7..c4e485876d8 100644
--- a/addons/project_gtd/project_gtd.py
+++ b/addons/project_gtd/project_gtd.py
@@ -116,7 +116,7 @@ class project_task(osv.osv):
                 search_extended += '''<filter domain="[('timebox_id','=', ''' + str(time.id) + ''')]" icon="''' + icon + '''" string="''' + time.name + '''" context="{'user_invisible': True}"/>\n'''
             search_extended +='''<separator orientation="vertical"/>'''
 
-            res['arch'] = res['arch'].replace('<separator name="gtdsep"/>', search_extended)
+            res['arch'] = tools.ustr(res['arch']).replace('<separator name="gtdsep"/>', search_extended)
 
         return res