Yahoo Chief Executive Marissa Mayer tried to slow the rollout of its search deal with Microsoft and questioned its partner's commitment, court filings show. In signs that their strategic relationship is under pressure a judge had to be called in to rule that Yahoo must adopt Microsoft's search technology in Taiwan and Hong Kong under their partnership.

Yahoo wanted to hold off switching to Microsoft technology in certain markets until Mayer had a chance to discuss the partnership with Ballmer's successor. Microsoft said that the disagreement was narrow and it had unwavering plans to continue investing in the Search Alliance, now operating in more than 20 countries.

Yahoo and Microsoft began a 10-year search partnership in 2010, before Mayer took over as Yahoo's CEO. The two companies hoped their combined efforts could mount a more competitive challenge to Google, the world's No. 1 search engine. However it didn’t work that well and Google still controls roughly two-thirds of the US search market.