De-indexed homepage in Google - very confusing.

[McTaggart]

A website I provide content for has just suffered a de-indexed homepage in Google (not in any of the other search engines) - all the other pages remained indexed as usual. Client asked me what might be the problem and I just couldn't figure it out - no linkbuilding has ever been carried out so clean backlink profile, etc. I just resubmitted it and it's back in its usual place, and has maintained the rankings (and PR) it had before it disappeared a few days ago. I checked WMT and no warnings or issues there. Any idea why this might've happened?

[McTaggart]

Having disappeared, the homepage appeared immediately when I resubmitted it, then fell back in SERPs a little and is now achieving better SERPs than when it disappeared. I can't see any probs with the code / sitemap or anything. All in all rather confusing but (thankfully) resolved in a couple of minutes. Thanks for your brilliant feedback Thomas and for your help as well Marcus. Thanks to you, I'm well prepared should this problem hit one of my clients again

[BlueprintMarketing]

Hi Marcus,
That is great news to have. Not that it's great that it happened but Great that other people have seen this happen and recovered. Considering all the things going on right now I would say at a glitch is entirely possible.
 I know Google makes a change to the page rank algorithm approximately every 3 months and weird things happen. Plus if you count the way people actually charge their page rank it's normally with some bar that's out of date.
 Here, it is what I found it appears to be extremely common with no issues that would actually affect you like your SERPS rank for certain keywords.
http://productforums.google.com/forum/#!topic/webmasters/ffzgDbpHh14
http://www.search9.co.uk/why-has-my-pagerank-disappeared
http://www.webworkshop.net/google_faq.html
http://www.webmasterworld.com/google/4550136-3-30.
http://www.zemanta.com/blog/find-google-algorithm-updates-make-website-search-rank-drop/
Marcus very valuable contribution thank you.
a change to the page rank algorithm approximately every 3 months and weird things happen. Plus if you count the way people actually charge their page rank it's normally with some bar that's out of date.
 Here, it is what I found it appears to be extremely common with no issues that would actually affect you like your SERPS rank for certain keywords.
http://productforums.google.com/forum/#!topic/webmasters/ffzgDbpHh14
http://www.search9.co.uk/why-has-my-pagerank-disappeared
http://www.webworkshop.net/google_faq.html
http://www.webmasterworld.com/google/4550136-3-30.
http://www.zemanta.com/blog/find-google-algorithm-updates-make-website-search-rank-drop/
the 3rd link down just like Marcus explained has a very similar story. I think very valuable contribution thank you Marcus your comment inspired me to look for more data.
All the best I hope this is of help,
Thomas

google_faq.html

[Marcus_Miller]

Hey, Thomas's response really nails most of the obvious causes here but as a simple n=1 oppinion this happened to one of my clients last week. Homepage disappeared for around 48 hours. No problems I could detect, but it was not indexed. Weird, but just as I was scratching  my chin it popped back up.

Check the obvious things, make sure there are no problems and then leave it for 48 hours and see if it pops back up.

Not hugely scientific but after such a big update we often see little aberrations and this could be one of those if everything else is as it should be.

Hope that helps
Marcus

[BlueprintMarketing]

I have heard a lot of people complain about page rank loss during the recent Penguin 2 update. Unfortunately that could be just Google's way of changing their own page rank. if the page itself is unaffected rank wise I would not be worried. The other thing I would what your client know is those page rank toolbars are notoriously wrong so you might want to check it through a more powerful or trustworthy source. I don't really put a lot of stock in Google's page rank because they frankly have told us not to and I would look more at the Moz rank

if there is a problem with the robots.txt it would be very possible Google is slow to reinstate it after what happened.

I would still check site with everything below however this is something I've heard of already from 2 other people. So it could just be a glitch or Google has made changes to its page rank algorithm.

It sounds to me as if there's either a problem with the robots.txt

or it's a simple matter of the plug-in or whatever's being used saying not to index or follow the homepage

if you could use this tool and simply type in the URL plus robots.txt

like this below

http://example.com/robots.txt

http://www.internetmarketingninjas.com/seo-tools/robots-txt-generator/

then post the results or send me a private message with them included.

In addition go on the homepage and search with either control F if you're a PC user or command F if you are Mac user for nofollow  and noindex

if you find either one of these

they will look like this

http://www.robotstxt.org/meta.html

<title>...</title>

 you can use the

http://www.internetmarketingninjas.com/seo-tools/robots-txt-generator/

to change them to make sure they're not on the page. You do not need them there as Google default indexes and follows every page unless you tell it not to. The other thing you have to look for use of  the X tag as well it can do the same thing as shown below

Example uses of the X-Robots-Tag

If you want to prevent search engines from showing files you’ve generated with PHP, add the following in the header file:

| 1 | header("X-Robots-Tag: noindex", true); |

This would not prevent search engines from following the links on those pages, if you want to do that, do the following:

| 1 | header("X-Robots-Tag: noindex, nofollow", true); |

But doing it in PHP is probably not the easiest use for this kind of thing. I myself greatly prefer setting headers in Apache, when possible. Consider, for instance, preventing search engines from caching / showing a preview for all .doc files on your domain, you would only have to do the following:

take a look at this to know if you are pages being affected by one or the other.

http://yoast.com/x-robots-tag-play/#examples

I hope this is of help,

let me know if I can be of more assistance.

Thomas