If a WordPress site breaks right after a plugin update, most developers jump straight to blaming the plugin itself. In practice, it's more often a conflict between two plugins than a bug in either one — and the two require different fixes.
Quick way to tell the difference: deactivate every plugin except the suspect one. If it still fails alone, it's a bug. If it only fails alongside a specific second plugin, it's a genuine conflict.
My diagnosis checklist:
- Enable WP_DEBUG and WP_DEBUG_LOG, check debug.log for the plugin folder in the stack trace
- Bulk-deactivate all plugins (or rename the plugins folder via FTP if locked out)
- Reactivate one at a time, testing after each
- Once found, isolate it — run it completely alone to confirm it's a true two-plugin conflict, not a standalone bug
- Rule out the theme separately by switching to a default theme temporarily
For WooCommerce sites specifically, I never run this process live — always on a staging clone, since deactivating a payment gateway or caching plugin mid-checkout can cost real orders.
Common conflict patterns I run into constantly: two SEO plugins fighting over schema output, two caching plugins both trying to control the cache layer, and page builders colliding with a theme's own builder over jQuery versions.
Full write-up with a fix-priority order (update → check forums → adjust load order → replace → custom code) and a scenario table: https://amanurrahman.com/blog-post/wordpress-plugin-conflict-troubleshooting
Curious what conflict patterns others run into most often — always seems to be caching or SEO plugins in my experience.