ArtRage5 Installation Problem on Mac

[*Rich]

Hello,

I ran the downloaded installer file of ArtRage5 (install_artrage_5_macosx.dmg), but got the following pop-up window error message:
"There may be a problem with this disk image..." (see screen shot)

This message popped up at the end of the file installation, with "Checking volumes..." indicated on the installation progress bar.



OS: macOS 10.13.6
MacBook Pro 15" Retina, 16GB RAM

Thanks.
Rich