If you see an error in WordPress > Appearance > Themes saying "The following themes are installed but incomplete." with Divi listed in there, the best way to address it is to download the latest Theme zip file from the members area: https://www.elegantthemes.com/members-area/ and then reinstall the theme.

You can reinstall the theme by going to Appearance > Themes > Add New and then upload the .zip file downloaded. For more detailed instructions, you can also check our article: How To Reinstall A Theme