“It’s crippling the entire city for sure,” Caplan said. “There’s just no resolution. It seems like there’s no contingency plan in place for Baltimore city.”

In a briefing for City Council members on the attack Monday, Mayor Bernard C. “Jack” Young said officials were “working to minimize any impact on real estate transactions.”

On Tuesday, a spokesman for the mayor said the city’s finance department was trying to gain access to its mainframe system “to accurately provide an accounting of outstanding liens against properties scheduled for closings.”

“They’re working with outside experts and hope to gain access to the information as quickly as possible,” spokesman Lester Davis said in an email.

Georgiana Tyler, president of the Greater Baltimore Board of Realtors, said the organization has been in regular contact with city officials who understand the seriousness of the situation. Tyler said the city appears to have a plan for how to gain access to the necessary data and that she’s hopeful the problem “will be solved sooner rather than later.”

In the meantime, hundreds of property sales could be affected. A real estate agent with access to industry data said at least 1,500 sales are pending in Baltimore.

Realtor Joy Sushinsky said she had lost one deal already because of the computer problems and had several more on the line. If a second deal scheduled for Wednesday doesn’t go through, she said, the buyer and seller could be on the hook for some $2,600 in extra costs. And Sushinsky said because of lost revenue, she’s dipping into savings to pay her assistant.

“It’s just a mess,” she said.

The Greater Baltimore Board of Realtors said in a statement that it was seeking an emergency meeting with city officials. Al Ingraham, the group’s director, said in a subsequent email that he did not expect to know anything more until late Wednesday.

The board’s statement said most major title insurance companies had told their agents not to issues policies until the city’s computer issues are resolved. Without such a policy, a transaction involving a mortgage can’t be closed.

First American Title Insurance Co. was among those firms instructing agents not to close any deals in Baltimore.

“While the City is aware of the problems created by the inability to accept or process real property sales and loan transactions and is working on a solution, it is unable to give a time frame on when it will be able to re-open. We have been told to check in weekly,” the company wrote.

“We understand that the situation presents difficulties for our agents, but feel that under the circumstances, declining to insure until systems are back in full service is the only way to approach the problem.”

An official at the city’s housing department has said its ability to cut checks for home-buying incentive programs also has been affected by the hack.

The ransomware was detected May 7. Hackers locked up files on city computers, demanding a payment to turn over the keys, but officials have said they won’t pay.

The disruption to the computer network has caused widespread problems in city government. City employees do not have access to email, leading some to create private accounts to get work done. The hack has affected the city’s ability to accept payments, and officials have said they are suspending late fees. Several agencies are developing workarounds to continue offering services that typically rely on computers.

Officials have said it could take weeks to restore all the computer systems.

“This is a very unfortunate situation, but other cities have had this exact circumstance happen,” said Cindy Ariosa, treasurer for Bright MLS, the region’s multiple listing service for real estate. “It’s a sign of the times.”

She said a workaround could involve a paper system or a tech-driven solution.

In the meantime, she said, “people will be impacted, but the city is at risk, too. People have to pay thousands in transfer taxes; they pay property taxes; they pay water bills and ground rent.”

Spencer Stephens, corporate counsel for the title company Bay County Settlements Inc., said his firm has a few transactions that are being held up by the ransomware attack.

“If you’re buying and you gave notice at your apartment and you’re planning on moving at the end of May, that timing is in question,” Stephens said. “If you’re a seller, it’s a problem because you want to move to your new house, and you want to get the funds out of our old home and make moving arrangements.”

And the problems with home sales in Baltimore could ripple through the housing industry. Alyssia Essig, a realtor and former president of the Realtors’ board, said that’s because each property sale is like one in a set of dominoes. Each must fall in turn.

“The house that is due to close in Canton is the beginning domino for that person who is buying a home in Towson, and that person is buying a home in New York, and that person is buying a home in Canada,” Essig said.

Clifford Rossi, professor in the University of Maryland Robert H. Smith School of Business and former executive in the financial services industry, said governments need to be better prepared. Hackers know they aren’t, which is why they target them.

“Not just Baltimore City, but most governments don’t run themselves as a business and businesses would have a solid business continuity plan in place,” he said.

“They’d have backup systems, dedicated data warehousing for sensitive information,” he said. “I’m not casting aspersions on these folks … but at the same time continuity plans and redundancy and back-up plans are critical, particularly in this day and age.”

A certain number of people will walk away once the lock-in period in their home purchase contracts expires, he said. That is at least delayed revenue to city coffers and potentially lost revenue, and, he said “another black mark for Baltimore.”

Baltimore Sun reporter Meredith Cohn contributed to this article.