Purview can block external access to SharePoint files
Reviewed by Helen Jones
Microsoft updated Message Center item MC1338823 on July 14, 2026. Purview Data Loss Prevention can now block access to sensitive SharePoint Online and OneDrive files for specific external domains or individual external email addresses, with worldwide general availability due from mid-July to the end of July 2026.
Before this, many small Microsoft 365 admin teams had to manage external sharing mainly through tenant settings, site settings, links, guest access, and manual reviews. That made it awkward to handle the common case where one partner, supplier, or external user should not open a sensitive file even though wider collaboration still needs to continue. The new DLP action gives admins a sharper control point, but it also creates a new support moment. If a partner suddenly sees access denied, the helpdesk needs to know whether the block came from SharePoint permissions, guest access, conditional access, or a Purview DLP rule.
Analysis
Pick one sensitive external-sharing scenario and decide whether a domain or user-level DLP block would reduce risk. Then update the helpdesk script so access-denied tickets include a Purview DLP check.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "Purview can block external access to SharePoint files", Collab365 Spaces. 1 source referenced.