How to Fix WordPress Issue: Cannot Add New Page or Post (Corrupted Database)

If you’re facing issues adding new posts or pages in WordPress, and you’ve ruled out plugin and theme conflicts, it might be a database problem. Follow these steps to troubleshoot and resolve the issue:

Step 1: Identify and Confirm the Issue

1. Disable Plugins and Themes: Start by deactivating all plugins and switching to the default WordPress theme (e.g., Twenty Twenty-One). Confirm if the problem persists.
2. Check for Core Updates: Ensure there’s no ongoing core update by verifying the absence of ‘core_updater.lock’ in ‘wp_options’ table.
3. Investigate WordPress Logs: Enable WP_DEBUG in your WordPress installation and check the error logs for any issues. Look for entries indicating a database error, especially involving a duplicate entry for the ‘PRIMARY’ key.

Step 2: Analyze Database for Duplicates

1. Examine wp_posts Table: Inspect the ‘wp_posts’ table for entries with ‘ID=0.’ If found, attempt to delete these entries. Note that deleting might not entirely resolve the issue.

Step 3: Resolve Duplicate Entry Issue

1. Backup Database: Before making changes, it’s crucial to back up your database. Use a tool like phpMyAdmin or a plugin for this task.
2. Identify and Remove Duplicate Entries: Run a query to find and remove duplicate entries in the ‘wp_posts’ table. Execute a query similar to:

DELETE FROM wp_posts WHERE ID = 0;

Step 4: Check and Repair Database

1. Database Repair: WordPress provides a built-in tool for database repair. Add the following line to your wp-config.php file:

define('WP_ALLOW_REPAIR', true); 

Access ‘yoursite.com/wp-admin/maint/repair.php’ in your browser and follow the on-screen instructions.

Step 5: Investigate Customized Plugin

1. Plugin Compatibility: Verify if a customized plugin caused the initial issue. Check for updates or contact the plugin developer for assistance.
2. Recreate Database Connection: Create a clean WordPress 5.7 install, linked to a copy of the database from the previous installation. Ensure no plugins are active. If the issue persists, the problem might be in the database itself.

Step 6: Seek Professional Assistance

1. Database Expert: If the problem persists, consider reaching out to a database expert or a WordPress developer. They can provide a more in-depth analysis and solution.

By following these steps, you should be able to identify and resolve the issue causing the inability to add new posts or pages in WordPress.