Hello there and thank you for sharing this information with us.
As relevantly new operating system fully updated El Capitan is capable of installing “older” software.
First update your Macintosh computer to the latest available software release as explained in this article here http://support.apple.com/en-us/HT201541 and change your computer settings in a way to allow installing software from unidentified developer as explained in this link here http://support.apple.com/kb/PH21769
Then install the program using the administrator account of the computer. This should help Architect 3D to mount and operate successfully.
The Avanquest Team
- Windows 10, Windows 8, Windows 7, XP (32-bit et 64-bit) or Vista
- 1 GHz Pentium Processor or equivalent
- 512MB RAM
- 5.5GB free hard disk space
- 3D Video card (1024*768 min 32-bit)
- Macintosh® OS X 10.9 or higher
- Intel® Core™ Duo Processor or higher
- 256MB VRAM
- 3.5GB free hard disk space
- 1GB RAM
- Display resolution: 1024×768
Note: The software in the Architect 3D range requires disk space of more than 1 GB. We therefore recommend that you use high capacity hard drive.