By Tom Whitfield

Google reversed a successful domain migration four months after it completed, cutting a site's new domain from roughly 5,000 impressions per day to 20 impressions per week. Google Search Advocate John Mueller said the case shows that migrations can take longer than expected to fully process.

The site owner described the sequence on Reddit. They changed their domain at the start of 2026, executed all redirects, filed a Change of Address in Search Console, and updated internal naming. Traffic recovered by the beginning of April.

Then Google undid it. The search engine restored the old domain's visibility, deindexed the new one, and reassigned more than 5,000 new-domain pages to "Crawled, Not Currently Indexed."

"So I have a website that was doing very well, especially on Google," the site owner wrote. "At the start of 2026, I changed the name and domain so that one additional topic could be covered. Did all the redirects, Change of Address, and internal name changes right away so traffic recovered quickly around the start of April."

They continued: "Four months later, Google suddenly reverted everything back to the old domain. More than 5,000 pages of the new domain were changed to Crawled, Not Currently Index and the new domain now gets 20 impressions per week."

The practical damage is limited but real. Old-domain URLs still rank, and clicks redirect to the new site, counting as regular views. Search Console, however, now attributes impressions and clicks to the old domain.

What did Mueller say?

Mueller responded directly and offered to inspect the domains. He confirmed that processing can run long, and he flagged one specific fix: file the Change of Address in Search Console for both the www and non-www versions of the domain.

He wrote: "Happy to take a look if you want to DM me the domains. Sometimes things just take a particularly long time to be fully processed. One thing which we noticed (and adjusted in the documentation a while back) that can help is to make sure that you have change of address set up in search console for both www and non-www, so that it can fully migrate the domain."

The takeaway in plain words: Google updated its own documentation on this point, and a two-minute check of both host versions can prevent a stalled migration.

Why does canonicalization matter here?

External links pointing to either the www or non-www variant can contribute to Google selecting the old domain as the canonical URL, according to the Search Engine Journal analysis of Mueller's advice. Canonicalization is the process by which Google picks one URL, from all duplicates, to index and rank.

Diagnosing a failed migration as a canonicalization problem is a reasonable approach. Signals pointing at multiple host versions split the vote, and Google can revert to the stronger, older domain.

What details did the site owner leave out?

The Reddit post omits several checks that commonly break migrations:

• Absolute internal URLs. Hardcoded links such as www.example.com/some-page.html can survive in navigation, footers, and contextual content. A full crawl of the old domain with Screaming Frog before migration catches stray absolute links that should be relative (/some-page.html).
• Redirect type. A registrar-level redirect may not preserve URL paths. URL-to-URL redirects are safer. HTTPS forwarding can also fail if the old domain lacks an SSL certificate.
• Chained redirects. Multi-hop chains can complicate processing.
• Navigation changes. Redirects can fail when the new site's navigational structure changes.
• XML sitemap updates. Sitemaps communicate preferred canonical URLs to Google. A sitemap still listing the old domain sends conflicting canonicalization signals during migration.

Google's own migration guidance states: "Submitting a sitemap can help make the discovery process quicker, and it's fine to move your site in sections." That advice only holds if the sitemap lists the correct domain.

The short checklist for any migration team: crawl before you move, redirect URL to URL, update the sitemap, and file Change of Address for both host versions. Mueller's offer to review the case directly suggests Google recognizes these reversions as a real, diagnosable problem rather than a one-off anomaly.