--- a/src/pyams_content/workflow/task.py	Mon Feb 19 16:52:00 2018 +0100
+++ b/src/pyams_content/workflow/task.py	Tue Feb 20 11:08:41 2018 +0100
@@ -21,6 +21,7 @@
 from pyams_content.shared.common.interfaces import IBaseSharedTool
 from pyams_content.workflow.interfaces import IContentArchiverTask
 from pyams_i18n.interfaces import II18n
+from pyams_security.interfaces import INTERNAL_USER_ID
 from pyams_sequence.interfaces import ISequentialIdInfo
 from pyams_workflow.interfaces import IWorkflow, IWorkflowInfo
 from zope.intid.interfaces import IIntIds
@@ -63,7 +64,7 @@
                 info = IWorkflowInfo(content)
                 info.fire_transition_toward(workflow.auto_retired_state,
                                             check_security=False,
-                                            principal='system:internal')
+                                            principal=INTERNAL_USER_ID)
                 info.fire_automatic()
                 report.write("- {0} ({1})\n".format(II18n(content).query_attribute('title', request=request),
                                                     ISequentialIdInfo(content).hex_oid))