McLaren have apologised to Red Bull after a problem with their engine control unit affected Mark Webber's start at the Australian Grand Prix.
Webber started second behind team-mate Sebastian Vettel on the grid at Albert Park on Sunday, but he went backwards when the lights went out at the season opener and was down in seventh place by the end of the first lap.
He eventually finished sixth and team principal Christian Horner revealed after the race that a problem with the ECU impacted the Australian's race.
"We lost all telemetry on the formation lap... that meant he [Webber] was blind for the start and that ECU issue shut the KERS down as well," Horner said. "So by the time we reset the whole system he'd lost ground at the start.
"It's something they need to get on top of because there has been a lot of issues during testing."
McLaren Electronics Systems, a division of the McLaren Group which supplies standard ECUs to all F1 teams as well as NASCAR and IndyCar, confirmed that a software problem contributed to Webber's woes.
"The electronic units themselves ran without incident in Melbourne, but there was a software-related issue that meant that Mark Webber's Red Bull Racing car's garage data system had to be re-started during the formation lap," a statement read.
"That disrupted his preparations for the start of the race, for which Mark and the team has our apology.
"We are working together with them to prevent any recurrence."
It added: "It is a very complex piece of equipment that controls the powertrain and DRS (drag reduction system) and acts as a car's primary data system."