Hi Luca, MoI version 2.5 is an old version released 5 years ago, and I haven't been working on it for several years now. If I remember right the last OS version that runs it is 10.9/Mavericks. The current MoI version is 3.2 which has been updated recently to run on High Sierra, you would need to upgrade to that in order to run on High Sierra.

The other solution to run v2.52 would be to revert your OS to 10.9 or earlier.

- Michael