Firefighters spent about 45 minutes extinguishing the fire on the 500 block of Quarry Road.
Canadian-born Young is one of the most respected rock-folk musicians of the late 20th century. He has been inducted into the Rock and Roll Hall of Fame; some of his best known songs include "Cinnamon Girl" and "Rockin' in the Free World."
Representatives of Young, who lives in La Honda, were optimistic about the damage. Young came by the warehouse Tuesday to personally inspect the damage.
"Mr. Young had a lot of his equipment in there, but all of it was, or a majority of it was, contained within storage containers that they use for traveling when they're on the road," San Carlos Fire Marshall Jim Palisi said.
The Belmont-San Carlos Fire Department estimates it was able to save about 85 percent of the property, which included several vintage cars, paintings, musical gear and even canisters of archive film and music footage. What was saved was transferred to a nearby warehouse.
"He had a lot of film material in there that the firefighters protected," Palisi said. "Quick action by firefighters did definitely reduce his loss."
Young did lose at least one collector car; it could possibly be where the fire started.
"Certainly there's going to be a source where we're going to be looking around one of the vehicles, because there was significant loss to one of the vehicles that's there," San Carlos Fire Chief Doug Fry said.
No one was injured in the fire. At this point, investigators do not believe it was set deliberately.