my workspace disappeared with newest AI

This happens to me with almost every program in CC every update from InDesign to Photoshop. I save my workspaces and often have to copy and paste them in again. This time however they've disappeared for Illustrator even from the application support folder. This is a persistent issue that is so annoying and such a time waster :(.

Did you save your workspaces?

You can do so via Edit > My settings > Export and then afterwards Import

But: Illustrator likes fresh preferences after an update.

What you can do is try and replace those settings individually. Here are the locations: https://www.vektorgarten.de/illustrator-settings.html