For the third time this year, the ongoing $41.4 million upgrade of Loudoun County’s aging financial management systems — which handle core computer functions such as accounting, procurement, assessments, taxation and human resources for the county government — missed a scheduled completion date.

The Board of Supervisors allocated $25 million in its fiscal 2010 budget to replace the system, but the cost of the upgrade has exceeded that amount by more than 65 percent.

In December 2013, the board approved an additional seven full-time staff positions and increased funding by $9.4 million in an effort to complete the upgrade by March 2015.

That funding increase prompted Treasurer H. Roger Zurn Jr. at the time to call the cost overruns “totally unprecedented” in Loudoun.

“You can’t fail,” Supervisor Ralph M. Buona (R-Ashburn), then-chairman of the finance committee, sternly told staff members after the board approved the funding increase. “We’ve given you what you need. You told me you’ve got what you need. You just can’t fail.”

Project manager Vince Marchesano informed the Board of Supervisors’ finance committee last month that a major test of the system had failed, and it would not be ready by the Sept. 15 deadline. On Tuesday, he reported that the steering committee overseeing the project has approved a new completion date of March 22.

Upgrades of the accounting and procurement systems have been completed, according to monthly project reports. But the second phase of the project, which includes human resources management and payroll systems, remains unfinished.

After the completion date was postponed until June, then September, Marchesano reported that several problems detected in testing the second phase of the system would prevent it from being completed by September. Marchesano works for Vivad Technologies, a company contracted by the county to help manage the project.

Supervisors are considering legal action against AST, the company contracted to do the upgrade, because of the delays. In July, the county notified the company that it was in material breach of its contractual obligations, Marchesano said.

The finance committee met in closed session Tuesday, as it has several times this year, to discuss “actual or probable litigation” and to consult with its attorney regarding the county’s contract with AST. Finance Committee Chairman Matthew F. Letourneau (R-Dulles) and Supervisor Kenneth D. Reid (R-Leesburg) confirmed that the committee is considering the county’s legal options.

Marchesano said the county can withhold payments to AST until each phase of the project is complete. County spokesman Glen Barbour said in an e-mail that the county has made payments to AST “as deliverables are met.” Letourneau declined further comment.

Reid said in an interview Tuesday that he had been reluctant to support adding $9.4 million to the project in 2013 because he didn’t see the public benefit. However, he voted with the majority to approve the money. That was a vote he had come to regret, he said.

“Why does the county need a bells-and-whistles computer system, when that money could go to build a school?” he said.

Although Reid said county staff members could “absolutely” have done a better job managing the project, he attributed most of the problems to actions taken more than four years ago, under the previous Board of Supervisors. He said the project was severely understaffed and underfunded from the start.

Buona declined to comment for this article.

Barnes is a freelance writer.