Microsoft is proceeding with the staged retirement of custom scripts across SharePoint Online and OneDrive. Here is what an admin needs to know.

Quick Introduction to SharePoint “custom scripts”

In SharePoint, “custom scripts” broadly refers to client‑side code (Javascript) added to pages. Custom scripts were actively used for sites customizations, and still present in “classic” features (like “script editor web part”). Today Microsoft consider custom scripting in SharePoint Online as a Security risk. Custom scripts can execute with the current user’s permissions, making it hard to govern what code runs, who added it, and where it loads resources from—opening doors to script injection, XSS, and compliance/performance issues. See more here.

Overview
A common issue in SharePoint, known as User ID Mismatch, occurs when a user account is deleted from the directory and later recreated with the same UPN (User Principal Name). This often happens when an employee is rehired or returned from a long leave or when a common name like John Smith is reused. In short, reusing a username in the directory can trigger a User ID Mismatch in SharePoint.

Introduction to the Microsoft 365 Blog

This blog is dedicated to the practical side of Microsoft 365 in enterprise environments, with the focus on SharePoint and its surrounding technologies - Search, Copilot, Purview, Teams, OneDrive, Viva Engage, Entra etc. Drawing from nearly 20 years of hands-on experience — from SharePoint on-prem to SharePoint Online — I share lessons learned, governance strategies, automation techniques, and tenant-wide optimization practices. Whether you’re an engineer, architect, or IT leader, you’ll find actionable insights on managing large-scale SharePoint deployments, navigating Microsoft 365 integrations, and staying ahead in a rapidly evolving collaboration landscape. No buzzwords, no politics — just real SharePoint engineering.