Google Dropping Pages After SEO Clean Up

[Andy56]

I have been using SEOmoz to clear errors from a site. There
were over 10,000 errors to start with. Most of these were duplicate content, duplicate titles and too many links on a page. Most of the duplicate errors have now been
cleared. This has been done in two weeks (down to around 3000 errors now).

But instead of improving my rankings, pages that were on the second page of Google have started to drop out of the listings altogether. The pages that are dropping out
are not related to the duplicate problems and get A grades when I run SEOmoz
page reports.

Can you clean up too much too quickly or is there likely to be another reason for it?

[WebbyNabler]

I usually am terrified to make any changes to "errors" on pages that are already performing well. As i think anyone will agree, no one, even G themselves fully 100% understand search results, ect.... Sometimes what an application may percieve as an "error" could actually be an unintended asset. Just my two cents after getting burned by correcting "errors"

[XNUMERIK]

When google is recalculating/reassessing your credentials (trust, popularity...) typically after a major update/change to your website/page, it is not uncommon that a page drops heavily before recovering to a much better position.

Best thing you can do is wait a few days and see what happens.

When you are doing "well" or "not so bad", you should always keep a backup before making any changes, this way you can go back to the older version much more quickly.

[DarinPirkey]

I totally agree with XNUMERIK.  I had I site I took over after a "black hat" SEO was working on it and we dropped from #8 in Google to #212 after all my corrects.  We're number #1 now for that same keyword within 3 months.

There is no "Data" to back up what I'm about to say, but it has worked nearly 100% of the time for me.

Here is what I think happens:

I corrected the technical stuff first (on-page) (site structure, internal linking and things like that)

The drop occurred when Google Crawled my site before I had a chance clean up all the backlinks, 301s coming into the site.

So, naturally I dropped because I basically blew my page authority.

Once I had a good fix on all the off-page corrections to match the on-page stuff, I fetched as Google (in Google's Webmaster Tools) and submitted all linked pages. (I only recommend doing this when you've had major changes like you've done)

It usually takes 4 to 5 crawls and I'm right back up where I was and usually higher then before. It doesn't take much longer with new links to the pages to rank it faster, especially if there is quality on-page SEO done.