Mojave is a supported operating system since Illustrator version 23.×.
We request your help. Please get in touch with us at any of the other support channels – https://helpx.adobe.com/support.html . Since this is not a generic issue that we can reproduce at our end, we will need someone to look into your machine to figure out what is going on here.
An error occurred while saving the commentLogan commented
Running Mojave and using Illustrator CC. I have the same problem , and it did not save a recovery file. Lost all my work, very simple illustrations. The file was only 9 MB. Please help!