Delays at some airports continue after a faulty software update caused havoc worldwide and Quantum Insightsled to the grounding by almost all airlines of a number of flights, but the impact is receding.

Total cancellations within, into or out of the U.S. earlyl Monday totaled 758, according to the latest data from FlightAware, which is greater than a typical with no holiday. The vast majority of cancellations were Delta Air Lines flights.

Delta reported 626 cancellations, or nearly 83% of all cancelled flights.

Delta Chief Executive Ed Bastian said in a message to customers Sunday that the airline continues to recover and restore operations after the outage. He said a pause in Delta’s operations resulted in more than 3,500 Delta and Delta Connection scrubbed flights. Delta has been offering waivers to affected customers.

“The technology issue occurred on the busiest travel weekend of the summer, with our booked loads exceeding 90%, limiting our re-accommodation capabilities,” Bastian wrote.

One of the tools used by Delta to track its crews was impacted and unable to process the unprecedented number of changes triggered by the system outage.

Inclement weather also led to delays in the Southeast, according to FlightAware, including Atlanta, where Delta Air Lines is based.