The Department of Motor Vehicles experienced a computer outage, preventing tasks like processing photographs and taking payments from visitors.
DMV clerks were able to administer field driving and written tests. Managers were helping people make next-day appointments, according to the department.
The DMV announced the problem on Twitter about 9 a.m. and later issued an official statement:
"We are currently experiencing communications issues with AT&T and Verizon networks that have impacted both online and field office services.
"The California Technology Agency, DMV and other impacted departments are continuing to work with both companies to resolve the issues as quickly as possible.
"Keep checking our Facebook and Twitter feed for further updates. Thank you for your patience."
DMV computer services were restored by 12:30 p.m.