Is there a Mac equivalent of DOSBox? I was trying to run some old software on my Air today and I got these messages:


  You can't open the application because the classic environment is no longer supported.





  You can't open the application because PowerPC applications are no longer supported.


Is there an emulator or other piece of software that allows me to run this? Windows has DOSBox. Is there a similar program for macOS?
A good way to run classic Mac OS 9 applications on modern computers is to run the SheepShaver Emulator. I'm assuming that since your mac says the Classic Environment is no longer supported, you are trying to run a Mac OS 9 or below app.

http://www.emaculation.com/doku.php/sheepshaver_mac_os_x_setup

ROM files and classic disc images are easy enough to find online, but I won't link you any just in case it is against copyright regulations.