# 404 trying to add a notebook to a new collection

**URL:** <https://talk.observablehq.com/t/404-trying-to-add-a-notebook-to-a-new-collection/10963>\
**Category:** Help\
**Created:** [November 6, 2026, 5:44pm UTC](https://talk.observablehq.com/t/404-trying-to-add-a-notebook-to-a-new-collection/10963 "2026-11-06T17:44:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![tom](https://yyz2.discourse-cdn.com/flex030/user_avatar/talk.observablehq.com/tom/32/2262_2.png) [@tom](https://talk.observablehq.com/u/tom)\
**Post date:** [November 6, 2026, 5:44pm UTC](https://talk.observablehq.com/t/404-trying-to-add-a-notebook-to-a-new-collection/10963/1 "2026-11-06T17:44:25Z")

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I created a new collection, Pathfind, which lives at [https://observablehq.com/@tmcw/-/collection/pathfind](https://observablehq.com/@tmcw/-/collection/pathfind) - and currently it’s empty. When I click “Add Notebooks” on that collection page, I arrive at the URL [https://old.observablehq.com/collection/@tmcw/pathfind](https://old.observablehq.com/collection/@tmcw/pathfind) on old.observable, which is a 404. Looks like a bug in the migration from old to new.

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**Author:** ![mbostock](https://yyz2.discourse-cdn.com/flex030/user_avatar/talk.observablehq.com/mbostock/32/9_2.png) [@mbostock](https://talk.observablehq.com/u/mbostock)\
**Post date:** [November 6, 2026, 6:28pm UTC](https://talk.observablehq.com/t/404-trying-to-add-a-notebook-to-a-new-collection/10963/2 "2026-11-06T18:28:07Z")

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Hi Tom. Is it possible that you’re just signed-out of Old Observable? You have to sign-in to Old Observable separately, and since your collection is private, you’ll see a 404 page if you’re not signed-in.