SAN FRANCISCO — Executives of California’s largest power company received withering criticism from state regulators Friday over a pre-emptive blackout that left millions without power, some for days.

The company, Pacific Gas & Electric, was rebuked at an emergency meeting convened by the state’s Public Utilities Commission to examine how decisions were made and carried out in last week’s power shut-off.

PG&E acted after weather forecasts pointed to a severe fire risk across much of its territory because of hot, dry conditions and high winds. Its equipment has repeatedly been blamed for deadly wildfires, leaving it facing liability claims that have helped put it into bankruptcy.

Whatever the company’s good intentions, the regulators left no doubt on Friday that the execution of the blackout — the largest such operation in the state’s history — was unacceptable.