After eight years and more than $20 million in cost overruns, the trouble-plagued upgrade of Loudoun County’s aging financial management systems encountered more problems in a critical test last week.

On Tuesday, county employees were given access to the new automated payroll system so they could view their paycheck information and begin entering data they had previously been submitting on paper time sheets. However, the “self-service” data entry process was suspended later in the week after a glitch in the system was discovered, county spokesman Glen Barbour said.

Additionally, some employees’ payroll deductions and holiday pay were calculated incorrectly, Barbour said in an email Thursday. There were also some problems with the interface between the new Oracle payroll system and a separate system used by public-safety employees to enter their time and leave, he said.

“Naturally, [any] impact on an employee’s paycheck is considered very important, so the team is working to address any errors as quickly as possible,” Barbour said. “The implementation team is confident they’ll find solutions by the next payroll.”

Public school employees will have to wait even longer to start using the new system. The school board was informed Friday that the planned activation date for school employees has been postponed until Oct. 2, public schools spokesman Wayde Byard said.

Processing the payroll for more than 5,400 full-time, part-time and temporary employees in the general county government and 14,000 in the school system is one of the last milestones in the lengthy process of upgrading the financial management systems.

The county embarked on the project in 2009, when the Board of Supervisors budgeted $25 million to replace the computer systems that handle core functions such as accounting, procurement, assessments, taxation and human resources.

The system upgrade has been plagued by delays, cost overruns and the threat of legal action by the county against AST, a company that formerly managed the project.

Deadlines for completing the last remaining phase of the project — which includes the human resources, payroll and benefits systems — passed years ago. The total cost of the upgrade has swelled to more than $46 million, which is $5 million more than it was in 2013, when longtime County Treasurer H. Roger Zurn Jr. called the overrun “totally unprecedented.”

In June 2016, the supervisors accepted a settlement offer from AST and contracted with Oracle America to complete the final phase of the upgrade, with a goal of completing the project this summer.

The project’s cost crept even higher last month, when the supervisors shifted $443,100 in funding to complete the upgrade.

Project manager Vince Marchesano informed the board’s finance committee July 11 that there were “several critical issues” that might prevent his team from meeting a July 24 deadline to activate the payroll system for the county government.

Marchesano also informed the supervisors that the school system had decided to delay the rollout of its payroll system until Aug. 21 to allow additional time for “defect resolution, testing, staff training and [to] reduce overall risk.”

Several supervisors were clearly unhappy with the prospect of further delays.

“I don’t know what else to say,” committee Chairman Matthew F. Letourneau (R-Dulles) said. “It’s not great news.”

After Board of Supervisors Chair Phyllis J. Randall (D-At Large) inquired about the nature of the problems, Marchesano replied that there had been issues with the calculation of employee compensation and benefits.

“That’s a major issue,” Randall replied. “This is not good news.”

Shortly after that meeting, county staff members decided to try to make the July 24 deadline. At the July 20 Board of Supervisors meeting, County Administrator Tim Hemstreet said staff members in several departments had been working around the clock “with a target of going live” with the new system early the following week.

For the first pay run using the Oracle system, the county’s payroll staff manually entered time sheet information for almost 1,900 hourly employees, Barbour said, adding that they would have to do so again for the next pay run if the problems with self-service data entry that occurred last week could not be fixed soon.