Erick Thohir stopped the swap of Guarin for Vučinić according to Gazzetta dello Sport:

“Thohir blocked the deal: The Inter president has, from Indonesia, stopped the negotiations that would take Mirko Vučinić to Inter in exchange for Fredy Guarin to Juventus. There was talk about a straight swap, definite transfers, yet the president was also for the idea of ​​a loan. The leaders of the two teams had gathered in an office in Piazza Cairoli, after the night’s turning point and had lunch together: Inter sporting director Piero Ausilio, CEO Marco Fassone and technical director Marco Branca, with Juventus CEO Marotta and sporting director Fabio Paratici. With them, Alessandro Lucci, the Montenegrin’s agent, and representatives of the Colombian Ferreyra and Dozzini.”

Source: Gazzetta dello Sport