From the USA Turnitin providers:
“Turnitin service may be intermittently unavailable during a scheduled maintenance period on Saturday, August 10th, from 7 to 11 AM Pacific Time (http://www.timeanddate.com/worldclock/fixedtime.html?msg=Turnitin+Maintenance+Period&iso=20130810T07&p1=224&ah=4). An announcement will appear for users within Turnitin in advance of when the system will be unavailable for this scheduled maintenance.
Instructors are encouraged to modify assignment due dates either before or at least several hours after the scheduled maintenance window.
Providing a fast, reliable and secure service is something that Turnitin takes seriously. Stay current with Turnitin’s system status, performance, security, and scheduled maintenance updates via the new Turnitin System Status page: http://turnitin.com/en_us/support/system-status“