A cyber attack has disabled online learning and left telephone and email services down, Durham District School Board said Sunday.
Literacy tests have been cancelled for Monday and most student chromebooks will not work, the board said.
In a letter to parents and guardians, the school board said it was first made aware of the "cyber-incident" on Friday and that IT teams have been working throughout the weekend to restore the services affected.
"We have notified law enforcement and are working to investigate and understand the full impact of this incident," the board said in the letter.
The board says with computer systems down, attendance will be taken manually. It says parents have been notified that staff may not have access to emergency contact information.
Meanwhile, the board says it appreciates that this incident "raises a significant privacy concern," and it will be providing updates and sharing more information when it's available