Not enough memory
Have issues with CC 2017 (latest version) not being able to action things as not enough memory. Seems to be that 2GB limit that Ai imposes as my system has 64GB installed with at least 40GB free to use. The programme is also incredibly slow with anything complex. I reinstalled CS6 version, and that works faultlessly and fast with the same files, with no hesitation at all! It's at least 20x times faster than current Ai. I'm on a powerful Mac Pro with Sierra 10.12.6 and an NVIDIA 4GB GTX 970 graphics card. I have disabled GPU use as it often crashes AI. I put performance ahead of new features. There are so many vector programmes out there that work so much faster than Ai. There must be a fix as something is definitely seriously wrong here.
Alastair L commented
Wow, this, on the face of it is not good at all. I also suffer memory problems and beach-balling on a fairly recent MBP with 16 GB even with no other apps running.
Try Affinity designer maybe. It's written from the bottom up as a native 64-bit app in Objective C/Swift using Cocoa APIs. Lots of C++ shared code with Windows, including their own (Java was it?) UI.
Can undo 8000+ operations in one shot (using history snapshot).