Debugging WordPress Problems (for Only You)

How do you figure out what is wrong in WordPress?

WordPress has some good diagnosing and troubleshooting information available to you, but the default is it is turned off. (For good reasons, including it is visually very distracting on screen, and it has candy for hackers.)

Most of what you might see are PHP errors, PHP warnings, MySQL errors. If you don’t understand what they mean, even emailing the messages to the plugin author or your technical support person can be extremely helpful.

Normally you can turn debugging on or turn it off, in your wp-config.php file.

I have a page that shows you exactly how to turn on WordPress Debugging for Only you, and only when you want it. Work normally most of the time, and when something is not working you can see what error messages you are getting.

Without debugging, you might get a message like this:
Download failed. Destination directory for file streaming does not exist or is not writable.

This specific message I got trying to update a plugin. Okay, which directory is the problem?

Turn on debugging, and you get this instead:
Warning: touch() [function.touch]: Unable to create file /home/USERNAME/public_html/wp-content/temp/plugin-name.tmp because No such file or directory in /home/USERNAME/public_html/wp-admin/includes/file.php on line 155
Warning: unlink(/home/USERNAME/public_html/wp-content/temp/plugin-name.tmp) [function.unlink]: No such file or directory in /home/USERNAME/public_html/wp-admin/includes/file.php on line 500
Download failed. Destination directory for file streaming does not exist or is not writable.

Ah, something with /wp-content/temp/.

And if you notice it affects all plugin updates, you might search for

wordpress "Download failed. Destination directory for file streaming does not exist or is not writable." and the first page when I searched, gives the correct answer. In this case, it’s add to your wp-config.php this: /* Setup a temporary folder for uploading and updating */
define( 'WP_TEMP_DIR', ABSPATH . 'wp-content/temp/') ;
and of course create that folder on your server.

If it only affected a single plugin, search that plugin’s support board. (I obviously changed the actual plugin file name to ‘plugin-name’, since the plugin wasn’t the problem. Normally you get the folder name of the plugin as part of the error message.)