Gary Illyes from Google confirmed that Google has “suddenly” dedindexed a “vast amount of URLs” from the Google Search index this past February. He said this was done because Google’s “perception of the site has changed.”
Gary said this at the SERP Conf back in mid-April.
Gary said on stage at the 10:40 mark into the interview, “Since February, where suddenly we just decided that
we are de-indexing a vast amount of URLs on a site just because the perception, or our perception of the site has changed.”
Here is the video embed:
Here is the full transcript:
And in general, also the the general quality of the site, that can matter a lot of how many of these crawled but not indexed, you see in Search Console. If the number of these URLs is very high that could hint at a general quality issues. And I’ve seen that a lot uh since February, where suddenly we just decided that we are de-indexing a vast amount of URLs on a site just because the perception, or our perception of the site has changed.
Ah so after February there’s a possibility that things could have changed in Google Search Console as well because your perception not you personally but Google’s perception of the site has actually fundamentally changed.
So Search Console is using the data that Google indexing and Google ranking or Google serving produces right . And then it’s distilling that data into something that is intelligible by me or by you or by anyone else because the like the raw data this just doesn’t make any sense to to us as as humans.
And like one possibility is that when you see that number rising that Google’s perception of the site has changed. Like that could be one thing. But then there could it could also be that there was an error for example on the site and then it serve the same exact page to every single URL on the site. That could also be one of those one of the reasons that you see that number climbing. So yeah there could be many things in the vast majority of cases it’s a technical thing.
Yes, back in February we had number of unconfirmed Google search ranking updates where tons of SEOs were complaining about seeing their pages drop out of the Google Search index.
Keep in mind, Gary is not saying you will get the “crawled but not indexed” errors because Google your site is considered low quality, it most likely is a technical issue with your site. But if you saw a spike of these “crawled but not indexed ” notices in Search Console in February, it might be related to site quality issues with your site.
We covered a bunch of other topics from Gary at this event a while back including:
Forum discussion at X.