When I download the DMG for MCreator 1.8.3 and I try to open it, it just sits there and never opens anything. Opening it is the first step in the installation instructions, but because it won't open, I can't get further.
Issue comments
I have redownloaded it a couple times. Same thing. And I don't think it's an antivirus thing, because it never displays any kind of warning or alert. It just sits there. The Finder window I open it from turns lighter like it usually does when you go to a different window, but no new app or anything actually shows up.
I have done some googling for you, check these:
https://techsupport.screenplay.com/hc/en-us/articles/115001839852-Probl…
https://apple.stackexchange.com/questions/242099/os-x-el-capitan-sudden…
https://discussions.apple.com/thread/8066591
https://apple.stackexchange.com/questions/271888/the-document-example-d…
https://apple.stackexchange.com/questions/64845/how-do-i-install-applic…
https://www.wikihow.com/Open-Disk-Image-(DMG)-Files-That-Are-Not-Allowe…
https://superuser.com/questions/1353732/unable-to-open-dmg-files-corrup…
Other users can open this file so I am kinda out of ideas as this is something related to your Mac.
You might want to try to redownload it, the file might be corrupted. I have tested it and it seems like it works. It could be that you have some sort of antivirus software that could be preventing the file from being open too.