Recently I was helping troubleshoot an issue in SharePoint Online where a site owner needed to delete files in the Style Library but was unable to upload, modify, or delete anything. So what could cause a site admin to get the error message Access Denied in Style Library? At first glance it looked like a permissions problem. The user had full control of the site, could work everywhere else without issue, and even had access to the Style Library itself. I even looked at Microsoft Purview to see if it was causing the issue. The real culprit turned out to be a setting that catches many SharePoint administrators off guard:…