SharePoint will count extra library data toward the 1TB site metadata cap
Reviewed by Helen Jones
Microsoft 365 Message Center item MC1478966, published 24 September 2026, says SharePoint will change how site metadata size is calculated. From 20 October 2026, the figure will include document library field data. The 1 TB metadata limit per site stays the same. No files are added, moved, or deleted. Reported size may rise. If a site then crosses 1 TB, it cannot add new metadata until usage drops. Existing content stays accessible. Sites Microsoft already expects to hit or pass the cap are left out of the first rollout. At 80 percent of the limit, admins can open a metadata size breakdown on the Storage Metrics page. Microsoft’s reduction list is familiar: unused list and library items, older file versions, and duplicate files.
The 1 TB metadata cap has sat in the background for years. Admins watched file storage, not the hidden weight of columns, versions, and list items. Large team sites could look healthy while the metadata clock was already running. After 20 October, that clock becomes visible. A reporting fix can push a busy library over the line without anyone uploading a file. Users still open documents. They just cannot add columns, update some list data, or keep growing the structure until someone trims versions and junk.
Analysis
This is a watch-and-check item, not a tenant-wide cleanup. Before 20 October, open Storage Metrics on your largest team sites and version-heavy libraries and note anything already near 80 percent so you are not surprised if new metadata writes start failing.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "SharePoint will count extra library data toward the 1TB site metadata cap", Collab365 Spaces. 1 source referenced.