Installing or updating a plugin can cause a fatal error if it is incompatible with WordPress, PHP, the theme or other plugins. If the site crashes, the most important thing is to restore access without making random changes.
1. Check whether WordPress has enabled Recovery Mode
When a fatal error occurs, WordPress can send the admin email address a message with a link to Recovery Mode. If you receive it, you can enter the back end in recovery mode and deactivate the plugin that caused the problem.
2. If you cannot reach the back end, deactivate the plugin via the file system
Connect via SFTP/FTP or the File Manager, go to wp-content/plugins/ and temporarily rename the folder of the plugin you have just installed or updated.
Example: example-plugin → example-plugin-disabled. WordPress will no longer find the plugin and will treat it as deactivated.
3. Read the error before reinstalling
If the site comes back online, do not just reactivate the plugin straight away. Check the server’s PHP logs or the debug file to understand which function, class or requirement caused the error.
On a production site, avoid showing errors to visitors. If you enable debugging, log errors to a file and turn debugging off once the analysis is done.
4. Check compatibility and requirements
- supported PHP version;
- minimum WordPress version;
- compatibility with the theme and the other plugins;
- any required dependencies;
- the changelog of the latest version;
- known issues reported for the plugin.
5. Restore a backup only when needed
If renaming the plugin solves the problem, you often do not need to restore the whole site. A full restore makes sense when the update also changed the database, configuration or other components and you cannot roll back cleanly.
6. Do not leave the renamed plugin as a permanent fix
Once you have found the cause, decide whether to update, replace or permanently remove the plugin. Leaving deactivated, forgotten folders on the server only adds confusion and attack surface.
If the crash started after an update or you cannot tell which component causes it, read also 5 common WordPress errors or contact me for a technical analysis.