SharePoint file opens read-only for everyone

Scenario

A document library item unexpectedly opens read-only for all staff despite expected edit permissions.

Recommended Resolution Path

1. Check whether the file is checked out, protected, or under a retention label.
2. Review sensitivity labels and Information Rights Management settings.
3. Confirm the users are members of the correct M365 group and not only visitors.
4. Test with a fresh browser session to rule out stale access tokens.

Technician Notes

Confirm the business impact, document the root cause, and capture any preventative follow-up in the PSA or client knowledge base.