In July 2007, conflicts with Yoon's management Eight Peaks surfaced; eventually Yoon filed a Certification Of Contents (COC) to cancel her contractual agreement with the company. The contents of the first COC stated that in January 2007 Yoon was confirmed to star in the MBC drama Que Sera Sera and had even completed the script reading and rehearsal for the upcoming shoot. However, the company forced Yoon to withdraw for Yoon to star in a company-produced drama, and as an effect, she was replaced by Jung Yu-mi. After her withdrawal, Yoon took a two-day vacation to Gangwon-do in March. Eight Peaks claimed that they had no knowledge of this so-called incident and spread a rumour of Yoon's irresponsibility online which damaged her reputation. Yoon filed a second COC in August, which included evidence to support the disagreeable actions made by Eight Peaks. These actions included the improper handling and distribution/division of earnings and proceeds as well as the unilateral (one-sided) manner of making and carrying out decisions which caused immense problems"