Open the and go to Plugins > Manage plugins to ensure "Pantone Connect" is installed. Restart Illustrator.

But beware: The internet is full of malicious .ASE files and scam "free download" buttons. This guide provides the official, safe, and professional methods to get Pantone colors back into Illustrator.

If you don't want to download and install the Pantone Color Manager, there are alternative methods to access Pantone colors in Illustrator: