CC 2017 has a known bug where auto-recovery files accumulate in ~/Library/Application Support/Adobe/Adobe Illustrator 21/. Set the recovery interval to 15 minutes (not 5 minutes) to reduce disk writes on older Macs.
Installing older software on a newer macOS can be frustrating. Here is how to successfully install Adobe Illustrator CC 2017 for Mac on a machine running High Sierra (10.13) or Mojave (10.14): Adobe Illustrator Cc 2017 For Mac
Adobe Illustrator CC 2017 for Mac is a vector graphics editor focused on precision drawing, scalable artwork, and layout for print, web, and interactive projects. It introduced performance improvements, new and refined drawing tools, and tighter integration with Creative Cloud services. CC 2017 has a known bug where auto-recovery
If you are installing this version today (perhaps for legacy hardware or specific client needs), these are the standout features you will use most: Here is how to successfully install Adobe Illustrator