After 180 days Google treats your old domain as an unrelated site — sweep every variant this week
Google's Change of Address stops treating your old and new domains as one site after 180 days, so this issue has you test every host variant of the old address for a one-hop redirect to the matching new URL, and names the fix for each result the test can return.
Google's Search status dashboard lists the September 2026 spam update as its newest ranking incident, and that update finished on 8 October. 1 The forums spent the following week attributing every wobble to it anyway.
On WebmasterWorld, ichthyous wrote that visibility "immediately dropped like a stone" as the update ended. 2 Martin Ice Web said the same, and that traffic kept getting worse. By 18 October, Chris travel 30 had decided "there is an update on the way." 2
Search Engine Roundtable read the same threads on 16 October and recorded a spike in chatter, with tools showing volatility and publishers describing hourly swings. 3
One report that week named a cause the site owner could test. An r/SEO thread posted on 10 October described a site that rebranded at the start of 2026, changing its name and domain to cover an extra topic. 4
The owner had done the redirects, filed Change of Address and changed the internal name. Traffic came back around the start of April, and the new domain was pulling about 5,000 impressions a day.
Then it flipped.
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. But if I open GSC on the old domain, everything is there. 4
John Mueller replied in the thread. Search Engine Roundtable reported the exchange on 13 October: he said "sometimes things just take a particularly long time to be fully processed," and pointed at one setting. "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." 5
That setting has a deadline attached, and the deadline is where this goes wrong.
The pitfall: the move signal lasts 180 days
Change of Address is how a site owner tells Google that two domains are the same site. Search Console's help page describes what it does: it "tells Google to emphasize crawling and indexing your new site over crawling your old site," and it forwards "various signals from the old site to the new site." 6
It also "tells Google to prefer the new site over the old when determining canonical pages." 6
The same page gives the duration. Those actions "continue for 180 days after you start migration in Search Console." 6
On day 181 the same page is blunt: "Google does not recognize any relationship between the old and new sites, and treats the old site as an unrelated site, if still present and crawlable." 6
Run that against the r/SEO timeline and the shape appears. A move filed in January loses that support in July. The reversal showed up in October, once that window had closed and the old domain was still crawlable.
Google also says outright that it keeps the old site in the index: "Google does not erase the old site from the index, and URLs from the old site can continue to be shown in Search results if they are available." 6
What holds the two domains together after those 180 days is the part you built yourself. The help page's own remedy is "providing redirects from the old site to the new and providing rel=canonical tags" to "reduce the number of old URLs shown in Search." 6
The second half of Mueller's answer is the piece most first-time movers get wrong. The tool moves one host at a time: "The tool does not move any subdomains below the specified domain (including www). So if you specify example.com in the tool, it will not move [www.example.com](https://www.[example.com](https://example.com)) or m.example.com." 6
The help page then asks for more than most people file. It wants the tool run for "all subdomain variants of the old domain, including www and non-www," and it adds "even if you're not actively using these variants currently." 6 Each variant has to be verified in Search Console first. Protocols are handled for you: the tool moves all protocols of the property you select. 6
Google's site-move guide sets the outer boundary: "Keep the redirects for as long as possible, generally at least 1 year." 7
A 180-day signal, a one-year redirect. The gap between them is the window that caught the r/SEO site.
The one action: sweep every variant of the old domain
The thread's own replies went to the same two things: confirm the redirects are still live, and confirm the canonicals point at the new domain. 4 This is how to check both for every address you moved away from.
Pick one page you moved, then ask every version of the old address to hand over that exact page. You need the old domain, the new domain, and a path that existed on both — an article, a product page, anything that survived.
- List the variants. Every old host that ever served your content:
example.com,www.example.com, and any subdomain you moved on its own, such asblog.example.comoren.example.com. 6 - Request the one path on each variant. In a terminal, run
curl -sI "https://example.com/best-espresso-machines" | head -n 5against each variant and read the response headers only. A good result is one301line with alocation:pointing at the same path on the new domain. Google asks for server-side permanent redirects,301or308, and advises against chains of more than three. 7 - Confirm each old variant is a property you own. Change of Address needs ownership of both sides under one Google account, and it works only on properties at the domain level. 6 Before accepting the filing, the tool runs pre-move checks on a few pages. 6 The tool sits at Settings → Change of Address, at
search.google.com/search-console/settings/change-address. - Resubmit the new sitemap. The new URLs are how Google learns the move completed, and the guide treats the old sitemap as finished once the new one is in. 7
What you find will decide the fix.
| What the sweep returns | What it means | What to change |
|---|---|---|
301 to the matching new URL, one hop | The old address still points at the new page | Nothing |
301 to the new homepage | The rule drops the path and sends every page to one | Rewrite the rule to carry the path across |
200 with the old content | The old site still serves pages Google can index 6 | Point that host at the redirects, or take the content down |
404 or 410 | That path never made it into the map | Map it, or accept the loss for that URL |
302, or a JavaScript redirect | Google follows it, and its guidance asks for a server-side permanent redirect 7 | Replace it with 301 or 308 |
Scope
Run the sweep if you changed a domain name or a subdomain since early 2025 and the old address still resolves. That covers the ordinary indie cases: a side project that moved onto a brand domain, a
.dev that became a .com, a blog that left blog.example.com for its own address.It bites hardest where the old host was left live — an old CMS still publishing, a parking page with content on it, a subdomain nobody redirected because nobody used it. Those are the hosts that give Google something to index once the move signal lapses.
Skip the subdomain steps if you have only ever used one host. Skip the whole check if your site has lived at one address from the start; your drop belongs to something else.
What to check afterwards, and how far the evidence goes
Three places, in this order.
- URL Inspection on a key new URL. Expand Page indexing and read Google-selected canonical: if it returns the new URL, Google treats that address as the canonical one. 8
- Page indexing on the new property. The count under "Crawled - currently not indexed" should start falling as Google recrawls, and validation "typically takes up to about two weeks." 9
- Performance on both properties. Google's guide asks you to watch traffic leave the old site and arrive at the new one, and that movement is what to measure. 7
Then the part this week's material leaves open. Marie Haynes published a second explanation on 13 October, from a site where 98% of URLs were unindexed after a migration that had correct redirects, a filed Change of Address and a fresh sitemap. 10 Her theory, which she says she cannot prove, is that a migration triggers a fresh quality assessment. Pages that offer nothing original, on her account, get crawled and declined. 10
The two explanations answer different questions. The sweep settles whether your old address still points at your new one. Haynes' theory asks whether Google wants the pages once it arrives.
Run the sweep first. It costs twenty minutes, and the headers answer it plainly.
One date makes the rest manageable. The move notification stays in both properties for 180 days, so write the filing date down when you file. 6 Run the sweep again in the week that window closes, because from then on the redirects are the only thing holding the two domains together.
References
- 1Google Search Status Dashboard
status.search.google.com
- 2October 2026 Google Observations
webmasterworld.com
- 3Google Search Ranking Volatility & Chatter Spike Today
seroundtable.com
- 4
- 5
- 6Change of Address tool
support.google.com
- 7How to move a site
developers.google.com
- 8URL Inspection tool
support.google.com
- 9Page indexing report
support.google.com
- 10
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