"We had problems with a routine software upgrade affecting desktop PCs," a representative of the department said Friday. "There have been delays with dealing with new or amended claims because many staff have not been able to access their systems. We have been working overnight with our suppliers to resolve the PC problems, and nearly all users can now access their business systems."
The representative confirmed that 80 percent of computers were brought down, and that its main suppliers areand .
Microsoft said the issue has now been fully resolved but was unable to provide any information on what caused the crash. EDS did not immediately respond to requests for comment.
"We worked closely with our partners to help rectify the situation and to support the DWP," a Microsoft representative said.
The Public and Commercial Services Union, or PCS, which represents civil and public servants in central government, said the number of employees is about 130,000 full-time equivalents, with approximately 100,000 terminals, which would put the number of desktop computers affected at 80,000. A DWP representative denied the figure of 100,000, saying it employs only 80,000 staff, but did not have any figures on the number of desktop computers in operation.
Work and pensions secretary Alan Johnson has ordered an internal inquiry into the role of Microsoft and EDS, which run the ministry's network as part of a deal valued at $3.78 billion (2 billion pounds), according to The Guardian.
By Thursday night, 95 percent of desktops were fully functional, and the department claims that the impact on customers has been minimal.
This disruption is the latest in a line of government technology failures, which included the failure of an IT project at the Child Support Agency valued at $850.83 million and the collapse of the $945.58 million Electronic Benefits Transfer System in August.
IT consultancy Avanade, the joint venture between Microsoft and Accenture, warned companies Friday that the urgent need to migrate from Windows NT 4.0 before Microsoft withdraws support has caused problems for companies.
"With the imminent retirement of support for Windows NT 4.0, the migration space has become increasingly frenetic over the past few months," an Avanade representative said. "Avanade has identified that its customers are under increasing pressure to migrate quickly but are concerned that with increased speed of migration comes risk."
Ingrid Marson of ZDNet UK reported from London.