Google de-indexed more than 5,000 pages on a site four months after a seemingly successful domain migration, dropping the new domain from roughly 5,000 impressions per day to 20 per week — while simultaneously re-indexing the old domain and shifting all search performance there.

The case surfaced in a Reddit thread spotted by SERP Journal. A site owner reported that a migration executed by the book had suddenly unwound months later. Google's Search Advocate John Mueller responded directly and offered one concrete fix.

What happened to the migration?

The site owner changed the site's name and domain at the beginning of 2026 to cover an additional topic. The transition initially worked:

• Redirects were implemented correctly.
• The Google Change of Address tool (Search Console's feature for telling Google a site has moved domains) was used.
• By April, traffic had recovered and the new domain was indexed, pulling about 5,000 impressions per day.

Then, four months in, the reversal hit. Google de-indexed over 5,000 pages on the new domain, flagging them as "Crawled, currently not indexed" (a Search Console status meaning Google fetched the page but excluded it from the index). Impressions on the new domain collapsed to 20 per week.

At the same time, Google completely re-indexed the old domain. All impressions and clicks now show up under the old property in Google Search Console.

What did John Mueller say?

Mueller replied in the thread and asked the user to direct message him — a signal Google wants to inspect the case at an account level. He also gave two on-record statements:

"Sometimes things just take a particularly long time to be fully processed," Mueller wrote, addressing the lag between migration and the reversion.

On a specific fix, he pointed to a documentation gap Google has since corrected: "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."

In other words, if the Change of Address request was filed only for one hostname variant — say the www version — the migration may not have fully propagated across Google's systems.

Confirmed facts versus speculation

Separating what's confirmed from what's inference:

Confirmed: the site owner's account of the timeline, the de-indexing figures, and Mueller's two statements, all from the Reddit thread.

Speculation: the cause. Mueller's www/non-www advice is the only technical explanation on the record, and it's unverified whether the site owner had actually missed that step. The original thread observer noted skepticism that a hostname variant alone could explain a full reversion of this scale, though Google has long shown old domains for navigational queries — which can't account for the reported click shift either.

Why it matters for site owners

For anyone running or planning a domain migration, the case is a caution flag on two fronts. First, a migration that looks stable at the four-month mark can still unwind. Second, Search Console hygiene around hostname variants — www and non-www treated as separate properties — has real processing consequences, per Mueller's statement.

The scale of the loss is the striking part: 5,000 impressions per day reduced to 20 per week is effectively a 99.9% collapse in visibility on the new domain, based on the figures the site owner reported.

Watch for the direct-message outcome between Mueller and the Reddit user. If Google confirms the www/non-www gap as the cause — or surfaces a processing bug instead — either answer changes how migrations should be documented and validated.