This feature should only be turned on if absolutely needed, due to the performance impact on each page load.
WordPress uses a caching system to map SEO / human readable page links into WordPress’s native links. This process is called URL rewriting, and the cache is referred to as the URL Rewrite Cache.
When using some plugins, this URL conversion cache can be come corrupted. The symptom of this is random 404 page errors for pages that actually exist.
There are a couple of steps to perform if you think you are suffering form this issue.
- On your WordPress Dashboard, go to Settings->Permalinks. Click Save to rebuild your URL rewrite cache.
Check and see if the symptoms come back. They may not come back immediately, but may take an hour or so to re-appear.
- Try turning on this setting to see if it solves the problem. Again give the site some time to see if the problem re-appears.
If this setting does solve the problem, we recommend spending some time testing to determine which plugin is causing the corruption, and report it to the plugin authors, so that they can fix it. Ideally they’ll fix the issue and you can disable this setting.