The disappearance of a master key and entry card in Wigglesworth Tuesday forced maintenance crews to change locks and left many students inconvenienced.
About 80 door locks and 300 student keys were changed when a custodial worker who had left the card and key unattended in the building returned to find them missing.
Workers said they believed the set, which had access to every room in the building, was stolen.
"We couldn't wait any longer," Robert F. Wolfreys, crew supervisor for Custodial Services in Facility Maintenance said. "It was enough time to make copies."
After the custodial worker reported the items missing at 1:30 p.m., Wolfreys immediately invalidated the card and changed locks, a procedure that cost the College $2000, he said.
Wolfreys said no thefts were reported and further use of the missing card will alert Harvard Security.
"Students mentioned they appreciated that people were looking out for them," Wolfreys said.
Maintenance workers told students that new keys would be available later that night at the Superintendent's office in the basement of Thayer Hall.
But some residents said they found the process inconveniencing.
"The lock wasn't changed until nine, and we had to have someone in the room all the time," Sawangthum Laohathai '96 said.
Jason C. Costa '96 said he and his roommates solved the problem by keeping their door unlocked until their new keys were made available.
Elizabeth C. Marlantes '96 said her rooming group was forced to climb through their bathroom window when they were locked out.
Still, Marlantes said, "I'm glad they took all necessary precautions."
Bill O. Selig '96 agreed, saying he appreciated the quick fix.
"It wasn't an inconvenience," Selig said. "And it was better than having someone break in."