Hi, Alejandro. Appreciate this extra piece of information!
While I'm glad to hear that updating Storyline 360 to the latest version solved your Media Library issue, we also want to help solve the freezing problem.
Because your setup sounds great and you already went through a repair, this is an excellent opportunity for our Support Engineers to jump in and analyze on your diagnostic logs! I've opened a case with the team, and you'll be getting an email from one of our engineers shortly.
I'll follow along to update this discussion with what we find out!