The site that disappeared
You approve a new website because the old one looked dated, and a week after launch the phone is quieter. Nothing on the screen explains it. A case reported this week describes an owner who did things in order. At the start of 2026 they changed the name and the domain, handled the redirects, the change of address and the internal name changes right away, and traffic had fully recovered by April.
Four months later Google suddenly reverted everything back to the old domain. The new domain went from around 5,000 impressions a day to 20 impressions a week, and more than 5,000 of its pages were marked Crawled, Not Currently Indexed. The pages were fine. Anyone clicking the old address still landed on the new one. Google had simply stopped counting them.
A rebuild moves addresses
Every page on your site has an address, and search engines keep a map of those addresses with what they have learned about each one. Rebuilding is not only changing how the site looks, it is asking for that map to be redrawn. Google has to decide which address is the real one now. John Mueller said that sometimes things just take a particularly long time to be fully processed.
That decision gets muddled without anyone meaning to. Internal links can stay written with the full old domain instead of being relative, the redirect can be set at the domain registrar rather than URL to URL, a certificate can fail, or two redirects can chain into each other. If the navigation changed shape, some old paths have nowhere left to land, and a sitemap that still lists the old domain keeps arguing for the site you just left.
Handled before going live
This is why address work belongs inside the build and not in the cleanup afterwards. Before the design is approved, the current site gets crawled and every address it has is written down, with one destination each and a single hop to get there. Links inside the content become relative, so they travel with the site wherever it lives.
Then the signals get aligned: the sitemap lists the new domain only, and the change of address in Search Console is set up for the www version and for the one without it. Mueller recommended that second detail specifically, because it is what lets the domain migrate fully.
What changes in your week
In practice the developer owns the address map and signs it off on launch day, not as a ticket for later. Whoever runs your marketing opens Search Console in the first week and checks two things: that the new pages are being indexed, and that the old addresses answer with one clean redirect. If something is crooked you find out in days, while the fix is still small.
What you notice is an absence. The forms keep arriving at the same rate. The link on an old business card, on an estimate you sent last year, in a directory listing, still lands on a real page. And the demand the old site spent years earning shows up at the new one instead of having to be bought back.