404 errors

There is something very strange, at least for me. Around august 2017 we moved our forum from vbulletin to xenforo 1.5. We then used a redirect script to redirect the /showthread url's from vbulletin to the new xenforo url's /threads. This worked fine and we did it to avoid that all the /showthread url's in google receives a 404 error. In januari we upgraded xf 1.5 to xf 2.0. However we did not implement the redirect script again, because almost all /showthread url's are not anymore in the google search results. And now the strange thing. Once we have made the update I see in GSC a large number of 404 errors. Most of them are the /showthread url's. For me it is a mysterie where google spidered/crawled these old vbulletin url's. In google there are only 5 left. In the sitemaps are 0 of the /showthread url's and in the database are 0 of these url's. I hope that someone have an answer for this 'problem'.


Active member
Maybe this will help.
If someone copy a thread URL from your forum with old URL structure (showthread.php) to his website, and that guy allows URL to be crawled by any search spider like google then expect to see those 404 errors since you removed the redirection script or htaccess rules.