Google Webmaster Tools -> Sitemap suddent "indexed" drop

[GlobeCar]

Hello MOZ,

We had an massive SEO drop in June due to unknown reasons and we have been trying to recover since then.

I've just noticed this yesterday and I'm worried. See: http://imgur.com/xv2QgCQ

Could anyone help by explaining what would cause this sudden drop and what does this drop translates to exactly?

What is strange is that our index status is still strong at 310 pages, no drop there: http://imgur.com/a1sRAKo

And when I do search on google site:globecar.com everything seems normal see: http://imgur.com/O7vPkqu

Thanks,

[GlobeCar]

I found the problem guys, I had made a change in the sitemap that messed up everything. It's all back to normal now. Thanks guys for your support!

[EcommerceSite]

That is what I was looking for, thank you.

[LesleyPaone]

I think this is the information everyone is looking for, https://www.seroundtable.com/google-sitemap-index-count-drop-is-a-bug-20608.html  It seems there is a bug in GWT with sitemaps.

[EcommerceSite]

I am having this exact problem, it started on July 14th. For some reason my indexed has dropped even though I have no sitemap errors. Have you received any answers?

[jorisbrabants]

Totally agree with Andy.

Make sure your XML sitemaps don't contain any errors, and if something like this happens you should closely watch your organic traffic as well. If there's a big drop in your organic traffic you can start worrying

[Andy.Drinkwater]

That isn't an 'SEO' drop as such, this is related to your sitemap errors. Doing a site: wont show the same numbers as you see as being shown on the sitemap itself.

Rebuild your sitemap, correct the errors and then see what state it is in.

-Andy

[UmarKhan]

Hey,

First of all you don't need to worry about. Be calm and find out the root cause.

Usually when this happen, we investigate things in bit depth. I can't give you the accurate answer before seeing the details. Please checkout the below pointers and let us know your thoughts.

1. Your marketing activities followed the same pace? May be, your competitors outranked you by producing more valuable links and pages.
2. Did you check the analytics? It'd be better for us if you could share the analytics traffic graph.
3. Have you done any major changes to your website in terms of design, technical things, content, URLs, shift to another platform etc?
4. Have you just recovered from any penalty in recent past? Check your WMT again.
5. Did you agency/team build new links in this time period? If yes, examine them.

Find out the best possible answer of above points and I'm sure you will get the clearer picture of this mishap.

Hope this helps!

Umar