WordPress Site Broken and it gives Headers Already sent error

What could be the issue.

You unzipped the theme and put its files in the root WordPress folder, overwriting important files and breaking your site. Doing this will always break your site.

It only needs to happen once for it to break your site.

The website had been functioning well for almost a year.

Irrelevant. It could have been running fine for 20 years before you unzipped into the root folder. The moment you overwrote WordPress files the site broke, it doesn’t matter how long it worked beforehand. Overwriting WordPress files with theme files breaks things.

How Do I Fix It?

You will need to remove the theme files that were incorrectly placed in the main WP folder /home/jcceastl/public_html/ then restore the original WordPress files using a copy of WordPress downloaded from wordpress.org.

So:

  1. Remove everything in the root folder except for wp-config.php, wp-content and .htaccess
  2. Download WordPress from wordpress.org
  3. Extract a fresh copy of WordPress into the root folder ( /home/jcceastl/public_html/ )

This will allow you to use WordPress again.

Alternatively if you made a backup beforehand, revert to that backup.

How To Update Themes Correctly

It should have been enough to upload a new copy of the theme via WP Admin. WordPress would see that it’s a newer version of one you already have and update it for you.

To do it manually you replace the folder for that theme with the new version in wp-content/themes. Each theme is a subfolder containing the files for that specific theme.

Note that when you download a theme that theme/zip contains only the theme, it doesn’t contain WordPress and doesn’t go in the root folder.