Illustrator CC 2017 (21.1.0) Crashing on Start

This reply is a long time coming.  Yesterday, after months of dealing with Illustrator 2017 crashing at startup, I FINALLY figured out the problem and the resolution! Read below because this was all me; No Adobe, Apple or Extensis support!

The crash report above is still valid. Same crash report given EVERYTIME I would attempt a test.  The only difference was the hardware and macOS used when testing...and the date/time.  I tested this on Yosemite, El Capitan, Sierra...and fixed it finally after installing High Sierra (trust me, the OS version had nothing to do with it!).

Look at this (from crash report): *** __CFTypeCollectionRetain() called with NULL; likely a collection has been corrupted ***

First and foremost (This is for you, ADOBE) - CFTypeCollectionRetain does not refer to TypeKit, FontBook, Suitcase Fusion or fonts...IT HAS NOTHING TO DO WITH FONTS!!! Whew...glad I can finally say that freely!

CFType refers to Apple's Core Foundation code!  Thats right...Type refers to programming types.  Like variables, object, etc.  Once I finally figured that out, then I went further down the crash report.  I skipped everything related to com.apple.CoreFoundation.  Next was com.adobe.Illustrator and thats as far as I got because those things are nearly impossible to understand.  However, there is more to discover if you take the time to try. 

About 5 more threads down, I found com.adobe.experimentation and decided to look into that.  Lets be clear...anything in an app that says experimentation cannot be good! Turns out, this is a built-in extension that Adobe added to Illustrator 2017...some say where Adobe can put untested extensions to try out...others say its kind of a sandbox environment to put your own custom extensions in for use with Illustrator.  I think it may be both and a means to get to an extension repository on the net to search for new ones.

Either way, ran a network capture against our proxy server (which was the workaround for us...disable proxy settings, open Illustrator, everything worked).  What was seen before but couldn't pinpoint was the proxy showing warnings about multiple authentication attempts after authentication had been granted. Turns out, there is a java script in this extension that attempts to authenticate to proxy after creative cloud does so when you first open Illustrator.  It doesn't attempt it until it begins loading the extension.

Okay, okay...likely no one else is having this issue unless you work for a Fortune 25 company, are the Mac support guy for a company that doesn't support Macs.  Otherwise, you'd have found and fixed this long ago...cause, well...you support Macs and work together to get things fixed!

So here's the fix:

1) Quit Illustrator if open and go to the Illustrator Application folder via Finder.

2) Open ~/CEP/extensions.

3) Right-click and "Copy" com.adobe.experimentation and paste it somewhere else (Desktop, Documents, external drive).

4) Delete com.adobe.experimentation.

5) Open Adobe Illustrator.

Thats it!  I tried deleting certain .js and other script files that may be calling the authentication attempt.  But sadly, it continued to crash or throw up errors that something was corrupted.  Only removing the extension completely doesn't disrupt anything.

I hope this helps...and Adobe Support; while I am fully aware that you are the defacto creative design suite anyone will ever want or need, your support is lacking in many ways! In my professional opinion, your staff needs to either be WELL VERSED in how to read and decipher crash reports correctly or its time you put some effort into developing something that we, the customers and primary line of defense for end users, can use to help us identify these issues.  4 cases and this thread over a 4 month period...and in the end, I figured it out myself.  I appreciate the effort, but this has been a lesson in "just figure it out yourself".  Because relying on others gets me no where!

And don't worry Adobe, I've sent the same message to Apple and Extensis.  The blame has been spread evenly.