A DMV spokesman says the problem hasn't been pinpointed as of Monday afternoon and it isn't clear when the system will be back in full operation.
Spokesman Pete Bucci says a mainframe server was upgraded Sunday and tested properly, but couldn't handle the load of actual business Monday morning.
The problem with license and registration transactions involves all 35 offices run by the DMV in major cities and the offices operated by county clerks upstate.
Bucci says "very few transactions are getting through." The agency will make allowances for anyone who misses a deadline.
He says engineers are working to identify the cause.