Fixing Common MetaSlider Fatal Errors: A Troubleshooting Guide

Users of the 'Slider, Gallery, and Carousel by MetaSlider – Image Slider, Video Slider' plugin occasionally encounter PHP fatal errors that can break their WordPress admin area or website frontend. Based on community reports, here are the most common errors and how to resolve them.

Common MetaSlider Fatal Errors and Their Causes

1. Call to undefined function errors (e.g., wp_add_inline_script(), gutenberg_get_jed_locale_data(), ctype_lower())

Why it happens: These errors almost always occur because your WordPress installation is outdated. The plugin uses functions that were introduced in specific WordPress versions. For example, wp_add_inline_script() was added in WordPress 4.5. If your site is running an older version, the function doesn't exist, causing a fatal error.

2. Call to a member function add_page() on null

Why it happens: This error typically occurs during REST API calls or specific admin actions when the plugin tries to register its admin menu before the necessary admin objects are fully initialized. It's a timing issue within the plugin's code.

3. Failed opening required file (e.g., helpers.php)

Why it happens: This suggests a incomplete or corrupted plugin update. During the auto-update process, some plugin files may not have been copied to the server correctly, leading to missing critical files.

4. Division by zero warning

Why it happens: This warning appears when a mathematical calculation in the image resizing logic attempts to divide by zero, usually because a slide's dimension setting is missing or invalid.

How to Troubleshoot and Fix These Errors

Solution 1: Update WordPress

The most common fix for "Call to undefined function" errors is to ensure you are running a modern, supported version of WordPress. The 'Slider, Gallery, and Carousel by MetaSlider – Image Slider, Video Slider' team recommends using a recent WordPress version for compatibility and security.

Solution 2: Reinstall the Plugin

If you encounter errors about missing files (like helpers.php), a clean reinstall often resolves the issue.

1. First, deactivate and delete the MetaSlider plugin from your WordPress admin panel (if you can access it).
2. Then, install it fresh from the WordPress Plugin Directory.
3. If you cannot access wp-admin due to the error, you will need to use your hosting control panel's file manager (or FTP/SFTP) to manually delete the /wp-content/plugins/ml-slider/ directory. After deleting it, you can reinstall the plugin from the 'Add New' plugins page.

Solution 3: Temporarily Disable for Debugging

If an error is preventing access to your site (a "white screen of death" or fatal error on the frontend), you need to disable the plugin manually to regain access.

1. Access your website's files via FTP, SFTP, or your web host's file manager.
2. Navigate to the /wp-content/plugins/ directory.
3. Rename the ml-slider folder to something like ml-slider_off.
4. This will deactivate the plugin and should restore access to your site. You can then investigate further, such as checking your WordPress version or reinstalling the plugin.

Solution 4: Check for Plugin Conflicts

Some errors, like the one involving yydev_show_pages_id_admin_notice(), are caused by conflicts with other plugins. To test for a conflict:

1. Temporarily disable all other plugins.
2. See if the MetaSlider error disappears.
3. If it does, reactivate your other plugins one by one to identify which one is causing the conflict.
4. Once identified, you can check if the conflicting plugin has an update, or you may need to choose between using the two plugins.

Solution 5: Enable Debugging (For Advanced Users)

To get more detailed information about an error, you can enable WordPress debugging. This is helpful if the error messages are vague. Always remember to turn debugging off on a live site after you have collected the information you need.

When to Seek Further Help

If these steps do not resolve your issue, the problem may be more specific. When seeking help in community forums, be sure to include:

• The exact error message from your logs.
• Your WordPress version.
• The version of the MetaSlider plugin you are using.
• The steps you have already tried.

This information will help others provide more targeted assistance for resolving persistent MetaSlider errors.