Excel Slow Protected View (16.0.15225.20204)

Good morning,

I have recently updated Office 365 to the latest version and since I did, all the excel files on the network are opened very slowly. I went from 2 sec to 10 sec.

By doing various tests I found that the problem is the protected viewing of the files. Since I can neither disable it nor identify the lost files as trusted, I wanted to ask if there was a way to fix the problem.

Thank you