Another common, easy to fix error, if you find out how to fix it in a post such as this one. Otherwise, it would have been quite impossible to figure this out. So if you happened to just removed or deactivated Wordfence, you are likely to run into this:

Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0 
Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0 
Fatal error: Unknown: Failed opening required '/home/.../public_html/wordfence-waf.php' ... in Unknown on line 0

So in your root directory there used to be a file “wordfence-waf.php” when you were using Wordfence. I found the reference in “.user.ini”, but I saw another article where apparently it used to be in “php.ini”.  So you want to delete or comment out:

// ; Wordfence WAF
// auto_prepend_file = '/home/universalforgive/public_html/wordfence-waf.php'
// ; END Wordfence WAF

and while you are at it, remove the Wordfence code from your “.htaccess”.

If you are in a bind you can get the site back by uploading “wordfence-waf.php” to the root directory. I am including a copy here, but you have to edit the file to insert your USERACCOUNT:

// if (file_exists('/home/USERACCOUNT/public_html/wp-content/plugins/wordfence/waf/bootstrap.php')) 
// define("WFWAF_LOG_PATH", '/home/USERACCOUNT/public_html/wp-content/wflogs/');
// include_once '/home/USERACCOUNT/public_html/wp-content/plugins/wordfence/waf/bootstrap.php';

Download wordfence-waf

When looking at “wordfence-waf.php”, you can see

// Before removing this file, please verify the PHP ini setting `auto_prepend_file` does not point to this.

How do you figure Wordfence thinks we are going to open all the files being removed when deleting a plugin? Shotty job. In addition, the Wordfence plugin page is full of upgrade banners and options. Not recommended. Stick with “All In One Security