Sitecore has a report called “Not Found URLs” located within the “Site Health” section of the Engagement Analytics component of Sitecore. Although in Sitecore 8, the Engagement Analytics is not present out of the box. It must be setup in order for Sitecore users to view the Site Health reports. Please refer to the following link for instructions of How To Enable Engagement Analytics within Sitecore 8. The “Not Found Urls” report is very useful to determine which pages are generating “Page Not Found Errors’ / 404 web response error codes. However in some Sitecore solution, this report seem not to yield any results and that may be due to several factors. This post will explain how to ensure that you Sitecore 8 solution appropriately tracked “Page Not Found” errors. For previous versions of Sitecore please refer to the following link Sitecore 7.2 Post For Not Found Url Report.
The following steps most likely will affect those Sitecore solution that are using a custom 404 processor to display a content managed item as the “Page Not Found” page. These solution usually find themselves having more than one site within a single Sitecore solution that has unique visuals of the “Page Not Found” display for each site.
In Sitecore 8, the process by which this report was populated has changed. Sitecore 8 now uses the “Page Not Found” page event to determine what should display in this report. This is very helpful since in previous versions this report was based on the name of the “Page Not Found” page that was requested rather than trigger of the “Page Not Found” page event.
As a result, the way to get this report to populate will be ensuring the “Page Not Found” page event is triggered whenever a 404 page is displayed to the user. Out of the box the Sitecore “Not Found.aspx” page will trigger this event but if you have a custom Page Not Found processor, then it is very important to make sure you include code to trigger the page event.
Below is a code example of how you can trigger the page event programmatically for the “Page Not Found” page event.
Once this occurs, this report along with other Site Health reports will display this error properly.
If the “Page Not Found” page is a content manageable page or content item, then you can specific the “Page Not Found” page event using the “attributes” tab and selecting the current failure actions page event(s).