Welcome to the Q&A Forum

I had a nice long reply, but the system crashed. I'll keep it short this time: Rel canonical is the right band-aid for this problem right now. However, you need to find out what is causing the issue and fix that because you don't want Google wasting crawl budget on thousands or millions of non-canonical URLs. I couldn't figure out which CMS / Shopping Cart system yours is built on, other than that it is on a Windows server. I don't have much experience working with eCommerce sites using Windows IIS except for Volusion. Perhaps it is a custom-built shopping cart, or just one I don't know of. Either way, the person who built it or sold it to you should be able to help you figure out why this is happening and help you fix it. If not, I might consider looking into a new eCommerce shopping cart system / CMS.

Fix broken internal and external links, like the Yoy-search url. That should solve one area of your 404 problems Identify why you have 404's in the first place. Find the root of the problem. Are these dead product pages? Definitely 301 them to the correct URL. If the product isn't there, consider redirecting to the homepage (or asking the linking site to change the URL to a relevant page) or showing a custom 404 page to show their other relevant offers.

Hey there Alex! Just wanted to make sure you were aware of this article from The Moz Blog. It helps quite a bit and serves as a checklist for keeping SEO elements in order. A checklist if you will http://moz.com/blog/web-site-migration-guide-tips-for-seos Hope it helps you as much as its helped me over the years! These migration projects are always a ton of fun  = |

A second opinion, Agreed with SEOVP , this is 100% redirect no need to have both pages if you can avoid this, 301 Redirect , James

Hi! The "Analyze Issues by Page" section actually just says that we didn't crawl that URL, not that it throws a 500 so there isn't an analysis we can provide. http://screencast.com/t/4dY8SZBs You can wait to see if that page is crawled during your next weekly update or run a crawl through the Crawl Test tool (in Research Tools). Crawl test will give you an analysis of up to 3k pages. There is a chance it still won't be crawled, but it is a way to get updated diagnostic data before the next scheduled weekly crawl. There was one 500 reported in the crawl and I can confirm it's still throwing that error, but it's a completely different page. Hope this helps clear things up!

A 301 is the way to go then. This helps Google understand how pages have moved. -Andy

Absolutely! I advise you do this as soon as possible as this will be seen as a black-hat technique by search-engines. No matter how high the domain authority of those websites, it will be seen as highly irrelevant and will be recognised as a technique to manipulate search. I would also look at getting in touch with the webmasters of the websites and trying to get them removed entirely before disavowing them. It takes more time and effort but disavowing can take up to 3 months (sometimes longer) and that is a long time in the world of SEO. Let me know how you get on.