Hi, Oh. I didn't dary say that maybe hardware problem. But I am happy, you could install Archicad 28.

It is sure according what we tried, your computer has some specific problem. I would say, it would be good to reinstall the Mac OS, but I know, it is not too comfortable step. Did you try the offers in the list what I wrote today?For example trying to mount from terminal?

The last answer from user was about downloading the Goodies Add-On Installer's dmg.We only wanted to check, whether any of downloaded dmg could mount. It was successful. The original error was: The user downloaded the AC 28 USA dmg, but it could not mount, because the Mac OS...

It is Ok. It means, this smaller dmg file could be downloaded, your Mac OS does not show "damage" error for it.You got "damage" error for the Archicad Installers' dmg files. Hm. Quite strange. We found information about "damage dmg" errors:Please, check these, maybe one of t...

I asked my colleague, he tried the USA 28 dmg on his Mac OS 15.0.1. He downloaded it, he could open it. Can I ask one more test?Please try to download the Goodies Installer's dmg from here: https://graphisoft.com/us/downloads/goodiesCan you open that dmg?