Also in 400, Duan would lose a major part of his territory. When his governor of Dunhuang Commandery, Meng Min () died that year, the officials in Dunhuang Commandery supported Li Gao, a county magistrate, as his successor. Duan Ye initially agreed, but was then warned by his general Suo Si () that Li Gao had greater ambitions and should not be permitted to stay at Dunhuang. Duan Ye therefore sent Suo to be the governor of Dunhuang. Li Gao made a surprise attack against Suo and defeated him, and then demanded that Suo be executed. At the advice of Juqu Nancheng (who also disliked Suo), Duan Ye executed Suo and apologized to Li Gao, who briefly remained submissive. However, late in 400, Li Gao, along with Tang Yao (), seceded with six commanderies, establishing Western Liáng, and Li Gao soon took over modern western Gansu and eastern Xinjiang.