Microsoft is defending itself against Japan’s Fair Trade Commission (FTC), which raided the company’s offices in February. Microsoft had dropped the clause from contracts but the FTC has insisted Microsoft also remove the clause retroactively from past contracts, a demand rejected by Microsoft.

The clause in question prevents companies taking action against Microsoft over patent and copyright infringement should they suspect their own software is in Windows.

The FTC said companies like Sony and Matsushita Electric Industrial have expressed concern their own audio software has no protection against Microsoft. Microsoft told a hearing on Monday the purpose of the clause is proper and accepted in the US.