Workers sifted through countless emails, permits that had been put on hold, as well as contracts and payments that had been delayed during the shutdown.

Forgotten or automatically reset passwords also created work bottlenecks. Many federal workers are required to change passwords at regular intervals, requiring calls to IT support teams, according to Venturebeat. The Washington Post said Tuesday that IT workers at the Department of Housing and Urban Development fielded more than 1,000 calls by 1 p.m. Monday to reset passwords or get computers online.

According to the UPI, employees at the Internal Revenue Service came back to millions of unanswered letters from taxpayers and tax-season workers who are weeks behind in their training. Similarly, the Food and Drug Administration may require months to catch up on the drug and medical-device applications that sat neglected.

The backlog faced workers in Washington and rural areas alike. “We all had to remember our old passwords and log in and change them,” Bob Beckley, who works at the U.S. Forest Service’s Technology and Development Center in Montana, told The Missoulian.

“Then I had about 500 emails to sort through. And those weren’t from my co-workers, who’d also been furloughed. They were from all the volunteers and cooperators and people looking for traditional skills information and training,” Beckley said.

The shutdown cost the U.S. economy $11 billion, of which $3 billion isn’t likely to be recovered, a report from the Congressional Budget Office said Monday. In total, the losses amount to a reduction in GDP of 0.1 percentage points in the fourth quarter of 2018 and of 0.2 percentage points in the first quarter of 2019.

It’s not clear how long workers will have to wait to receive their back pay from the shutdown, although many contractors are unlikely to receive any back pay at all. President Trump and Congress have until Feb. 15 to reach a compromise on border security, after which time the government could shut down again.