What this problem looks like
WordPress stores the active theme slug in the database. If that theme PHP is broken, every page can white-screen before you reach the admin themes screen.
Renaming the theme folder forces WordPress to fall back to a default theme that ships with core. You can then log in and pick a stable theme properly.
Find the active theme folder name
Connect via SFTP and open wp-content/themes/. The active theme folder matches the stylesheet directory name, not always the pretty theme name shown in admin.
Alternatively open phpMyAdmin, select your database, and read the template and stylesheet values in wp_options where option_name is template or stylesheet.
Switch by renaming the theme folder
- Rename my-broken-theme to my-broken-theme.off.
- Keep a default theme folder such as twentytwentyfour untouched.
- Reload the site URL in a private window.
- WordPress should load the default theme automatically.
Switch via the database
When you prefer not to rename folders, update the template and stylesheet options directly.
UPDATE wp_options SET option_value = 'twentytwentyfour' WHERE option_name = 'template';
UPDATE wp_options SET option_value = 'twentytwentyfour' WHERE option_name = 'stylesheet';Switch with WP-CLI
cd /path/to/wordpress
wp theme list
wp theme activate twentytwentyfourAfter you regain wp-admin
Open Appearance → Themes and activate the theme you want. If you use a child theme, activate the child, not the parent alone.
Review widgets, menus, and homepage settings. Theme switches often reset menu locations until you reassign them.
When to stop DIY and hire help
If the site still fails after a default theme loads, the problem may be plugin-related or database corruption. BugShield fixes theme and layout errors at a fixed price with direct developer chat.