WordPress site broken after an update? How to fix it

You clicked "Update now", or WordPress updated itself overnight, and in the morning your site has been replaced by a white screen or the message "There has been a critical error on this website". Or the site loads but looks broken, the menu is gone, or the contact form no longer sends.

A WordPress site broken after update is not rare, and most of the time it can be fixed within an hour. In this article I describe what to do, and in what order.

Why sites end up broken after update

A WordPress site is a core with ten to thirty plugins on top, built by different people at different paces. The update itself is rarely faulty. The problem is that two pieces that used to work together no longer do after the update. One plugin expects the new WordPress version, another still expects the old one. Or the PHP version on the hosting is older than the new plugin requires.

The longer it has been since the last update, the bigger the risk, because everything jumps several versions at once.

The first hour

1. Check your email

When a critical error happens, WordPress automatically sends an email to the admin address, stating which plugin or theme caused the error, together with a special login link (recovery mode) that lets you into the admin without the faulty plugin. If you got this email, you are halfway there.

If you did not, there are two possible reasons: the admin email is not yours, or your site cannot send email properly. Both need fixing anyway.

2. Turn off the faulty plugin

If you can log in with recovery mode, deactivate the plugin named in the email. If you cannot log in, open the hosting file manager, go to the wp-content/plugins folder, and rename the plugin's folder (for example by adding -off to the end). WordPress then treats it as deactivated, and the site usually comes back immediately.

If you do not know which one is at fault, rename the whole plugins folder. If the site comes back, re-enable the plugins one by one until it breaks again.

3. If that does not help: restore from backup

If the error is in the WordPress core or the theme, or several things broke at once, the fastest way is to restore the backup from before the update. That is why the backup has to be genuinely restorable and contain the database as well as the files.

After restoring, do not update the same way again. First find out what caused the error.

What not to do

• Do not reinstall WordPress "clean". It usually does not help, because the error is in the plugins, and you can easily lose content along the way.
• Do not delete the plugin, just deactivate it. Deleting often removes its settings too.
• Do not leave debug mode on for the live site. If you turned on WP_DEBUG to find the error, turn it off afterwards, because error messages are visible to visitors and reveal details about your server.

How to avoid it next time

Stopping updates is not the answer. Skipping them is far more dangerous in the long run: most WordPress hacks happen through old plugins with known vulnerabilities.

The answer is to try it somewhere other than the live site first. I run every update on a copy, check that the main pages, the forms and (for online stores) the cart and payment work, and only then on the live site. This is the bigger part of the work, and why a monthly maintenance plan is worth more than automatic updates.

What you can do yourself:

• Update regularly, in small steps. A monthly round is less risky than one big jump a year.
• Back up before updating. Even if your host also backs up.
• One plugin at a time, and check the site after each.
• Do not update on a Friday afternoon, or right before a campaign or the season. I wrote about this separately for online stores.

If your site is down right now and you cannot sort it out, write to me and I will take a look. And if you would rather this not be your problem next time, that is exactly what monthly maintenance is about. I wrote about the prices and what is included here.