Who can see what in Microsoft 365
Oversharing, Copilot exposure and the controls Microsoft gives you, explained from Microsoft's own documentation, with sources.
You can block Copilot Chat. That does not fix what Copilot can see
Microsoft Learn says admins can block Copilot Chat for all users or selected groups. That is an access switch; oversharing is a data switch. What the block does, what unpinning does not, where Restricted Content Discovery fits, and the licensing catch.
The new sharing link in Microsoft 365: what changes in October 2026, and what stays exactly as overshared as before
One main link per file, defaulting to only the people added. What the Message Center post says, the one per-site setting, and why the Anyone and organisation-wide links already out there are not touched.
Your Copilot in SharePoint site exclusion list stops working on 1 November 2026
The preview cmdlets that kept Copilot in SharePoint off chosen sites are retired at general availability and honoured only until 1 November. The two replacements, Site AI settings and Restricted Content Discovery, are not a list, and neither changes who can open a file. What each does, and what to check on every excluded site first.