Two different canonical tags on one page

[ShearingsGroup]

Due to an error, some of my pages now have two canonical tags on them. One is correct and the other goes to a nonsense URL (404 page).

I know I should ideally remove the incorrect ones, but it's a big manual job. Are they doing any harm? Can I just leave them there and let Google figure it out?

The correct ones are higher up in the code. Will this make a difference?

Any help appreciated.

[Dr-Pete]

Unfortunately, what Google can do and what they actually do can really vary. If you're mixing signals and doubling up the canonicals, the odds that they'll get it right are pretty low, in my experience. I think it's worth the fix, if these are traffic-generating pages.

[Thos003]

You should certainly fix this. You don't want google having to guess what you are trying to tell them. For the most part they will probably get it right, especially in your case with the 404s. But if this is occurring too frequently then they may begin to ignore your canonicals all together. Or worse, you may loose some google trust.

I'd put this on my fix it list.

[ShearingsGroup]

Thanks Scott. It's only wrong on a few hundred pages and they're all quite deep. If it were wrong on the important pages I'd fix it.

[ScottJames13]

You should change it, I'm no canonical expert, but the whole point of having it is to tell google how you want it to show, ex. www.yoursite.com or yoursite.com. If your not going to change it for all of your pages then at least do it for your home page as this is the one that usually gets the most attention.

[ShearingsGroup]

Well that's good news. Think I'll just leave them there then. Thanks!

[KyleChamp]

This is stright from Google Webmasters:

"What happens if rel="canonical" points to a non-existent page? Or if more than one page in a set is specified as the canonical version?

We'll do our best to algorithmically determine an appropriate canonical page, just as we've done in the past."

http://support.google.com/webmasters/bin/answer.py?hl=en&answer=139394

Hope that helps