Shopify "Alternate page with proper canonical tag": When It's Normal and When a Wrong Canonical Is Killing Your Rankings
Google Search Console's "Alternate page with proper canonical tag" status (Pages > Not indexed) means a page declares a canonical pointing to a different URL, so Google correctly skipped the duplicate and indexed the canonical instead. On Shopify this is usually expected: variant URLs (?variant=12345), collection-scoped product URLs (/collections/x/products/y canonicalizing to /products/y), and paginated or filtered collection pages all carry a canonical to the main page. It only becomes a problem when the canonical points to the WRONG page, for example when an SEO app, translation app, or theme update makes product or collection pages canonicalize to the homepage or a parent collection, deindexing pages you want ranked. Shopify generates canonicals from theme Liquid and apps can inject their own link tags, and Shopify keeps no history of your canonical configuration, so if a theme update or app rewrites it there is no native way to see the previous value or roll back.
If you didn't already have a backup, those old values are gone — Shopify keeps no history.
The steps below recover what you can. To make the next time a 1-click undo instead of hours of CSV work: a daily snapshot of every SEO field. Free to monitor, no card — and SEO Vault only reads your store unless you click restore.
Stop and diagnose: open the "Alternate page with proper canonical tag" list in GSC and inspect several URLs with URL Inspection, comparing the "Google-selected canonical" against the "User-declared canonical." If the declared canonical is correct (variant or pagination pointing to the main product), leave it. If product or collection pages are canonicalizing to the homepage or a wrong page, view the page source for the rel=canonical link and identify whether it comes from theme.liquid or a recently installed SEO/translation app.
Recover the correct canonical: for an app-injected wrong canonical, disable or reconfigure that app's canonical setting; for a theme issue, restore the correct {{ canonical_url }} tag in theme.liquid or roll back to a prior published version under Online Store > Themes. Confirm exactly one clean canonical per page in the live HTML source.
Validate and re-index via GSC: after fixing, run URL Inspection > Test Live URL on affected pages, click Request Indexing on the correct canonical URLs, and use Validate Fix on the report, then re-submit your sitemap.xml. If the same app also overwrote meta titles or descriptions, restore them by diffing a current Products export against a prior export or a Wayback Machine snapshot.
Catch it earlier with daily snapshots: theme rollbacks and canonical changes are hard to audit after the fact, and Shopify versions none of it. A daily backup of your SEO fields plus alerts when an app bulk-changes meta tags lets you spot a wrong-canonical event the day it happens. SEO Vault stores a daily history of products and collections so you always know the prior good state and can restore it in one click.
Source: Google Search Console Help — Page Indexing report ("Alternate page with proper canonical tag"), support.google.com/webmasters/answer/7440203
SEO Vault keeps a daily snapshot of every SEO field on your store — meta titles, descriptions, alt-text, tags, handles (products AND collections) — and emails you the moment something changes in bulk, with the likely app responsible. One click restores yesterday's state, just the SEO fields. Free to monitor and get alerted; $14/mo for 1-click restore.