Microsoft's German subsidiary submitted changes to its initial bid to the Munich city government in a last-ditch effort to keep the city's computer systems on Windows.
The city government will make the final decision today.
"We are asking for fair competition," said Microsoft spokesman Thomas Baumgärtner. "Our competitors were allowed to improve their initial bid after the 28 April deadline. We're asking for the same privilege."
On Monday, a committee of the Social Democratic Party, which controls the Munich city government, voted for an offer made by IBM and SuSE Linux to migrate the city's 14,000 computers to the open-source Linux operating system from Microsoft Windows.
If Munich were to select Linux, it would be the first big German city to drop Windows in favour of Linux. In December, the smaller southern German city of Schwäbisch Hall became the first city in the country to pull the plug on Windows and deploy Linux in more than 400 PCs.
In Germany, federal, state and local governments as well as other public agencies have been considering Linux intensively ever since the Federal Ministry of the Interior agreed in June to a partnership with IBM to supply computers with Linux.
Worried that a defeat in Munich could lead to more German city governments opting for Linux, Microsoft chief executive officer Steve Ballmer visited to Munich city Mayor Christian Ude in March.
Weeks later, Microsoft officials met with the Ministry of the Interior to close a new framework agreement for the public sector.
"This new agreement could bring savings of up to 30% to governments and other public sector groups, depending on size and other factors," Baumgärtner said. "Munich will benefit not only from this deal but also from our new offer that we've made today."
Under its latest offer, Microsoft is prepared to sell fewer licences to cover all computers in the city's entire network. "An analysis of the situation has shown that the city can get by with fewer licences than we initially calculated," Baumgärtner said. "
If it turns out that more licences are required in the end, we won't charge for these."
John Blau writes for IDG News Service