Tim Hortons says it is working with an external vendor to address a virus causing intermittent cash register outages.
In a statement to the Canadian Press, the fast-food giant says no consumer data or credit card information has been compromised.
It stresses that the issue has almost entirely been resolved and says only a small number of restaurants are still being affected.
According to the Globe and Mail, the outages have forced some franchisees to close or temporarily cease drive-through operations and others to suffer significant losses.
At one Edmonton location, Global News spotted signs apologizing for the long delays in the drive-thru and suggested customers use the Tim Hortons mobile app for faster service.
The publication says locations represented by the Great White North Franchisee Association are seeking compensation for the losses.
The association told The Canadian Press it would not comment for fear of franchisees putting their relationship with the board of directors in jeopardy.
— With files from Global News