Error on font style

[tarekabdullah]

all font changed from bold and medium to light when i updated illustrator 

[Monika Gause]

This happened in the Illustrator user interface or in your files?

[tarekabdullah]

When i preview the file in finder when click space it's looking good with the same font I want but when I open the file all medium and bold style goes to be light style

[Monika Gause]

Do you get any missing font warnings?

Are all those fonts OK? Are you sure?

Maybe reinstall them.

And also: are you using font management?

[Brad @ Roaring Mouse]

If you are relying on an auto-activated fonts, whether it be from Adobe Fonts or whatever, make sure you've activated the entire family. Is it a particular typeface you are having an issue with, and what is it?