In June 2001, she recorded the Mandarin version of the theme song, "Where the Dream Takes You", for the 2001 Disney science fiction film, "". The song was included on the pre-order edition of Tsai's fourth studio album, "Lucky Number", which was released in July 2001. Tsai received mixed reviews for the album, and it only sold more than 150,000 copies in Taiwan alone. The track, "If You Don't Want", reached number ninety-four on the Hit FM Top 100 Singles of the Year. Just after she released the album, Tsai's music career came to a halt due to the conflict with her management company of the time, D Sound. Tsai's father sued D Sound and claimed inappropriate contents in her recording contract and poor bookkeeping in the company. The dispute was resolved when Tsai paid NT$9 million in liquidated damages to D Sound. In December 2001, Tsai made a cameo appearance in the television drama, "Six Friends". In March 2002, Tsai made a cameo appearance in the television drama, "Come to My Place".