The package could not be installed. The theme is missing the style.css stylesheet.

Why this happens

This error appears when you try to upload a plugin file in the Themes section. WordPress expects a style.css file inside every theme, so if the uploaded file doesn’t contain one, the installation fails.

How to fix it

1. Make sure you’re uploading a theme file, not a plugin.
   • Theme files are installed under Appearance → Themes → Add New.
   • Plugin files are installed under Plugins → Add New.

Tip

If you meant to install a plugin, upload it through Plugins → Add New instead.