If WordPress responded The package could not be installed. No valid plugins were found, the cause is almost always the same, and it’s not a corrupted download: you’re uploading the author’s full package, not the installation ZIP inside it.
It’s worth saying this first because the natural next step is the wrong one: downloading again, trying another browser, opening a ticket. The file is intact; it’s just not the file WordPress expects.
Why the full package exists
Anyone selling a plugin on CodeCanyon or elsewhere usually ships a ZIP with everything: the installable, HTML documentation, the changelog, the license, sometimes a version for another CMS and an instructions PDF. That’s the full package. It’s meant to give the buyer everything in a single download, not to be uploaded to WordPress.
WordPress opens the ZIP, looks in the root for a PHP file with a plugin header, finds a documentation/ folder and a readme.txt, and gives up. Hence the message.
How to find the right file
Extract the ZIP you downloaded and look at what’s inside. You’ll find something like this:
documentation/: the documentation, not for installinglicensing/orlicense/: license textchangelog.txt: version historyplugin-name.zip: this is the one you upload
The practical rule: the installable is the inner ZIP whose name matches the plugin’s name, usually the heaviest one in the folder. If instead of a ZIP you find a folder with the plugin’s name, that’s the one that needs to become a ZIP: compress the entire folder and upload the resulting ZIP.
How to confirm before uploading
Open the plugin folder and look for a .php file in its root. It has a header starting with Plugin Name:. If that file is in the root of what you’re about to upload, WordPress will accept it.
If the error mentions a stylesheet instead of a plugin, it’s a theme case and the logic is similar, covered in “Stylesheet is missing”.
When the file is right and it still fails
If you’re sure you’re uploading the inner ZIP and the upload still fails, the problem has moved elsewhere: it’s usually the server’s upload limit. The symptom is different: the screen hangs, comes back blank, or mentions size, instead of saying the package is invalid.
If that’s not it either, open a ticket with the item’s name, the version, and a screenshot of the error screen. The literal message identifies the case almost every time.
