The Server Extension is an optional component that can be installed on your on-premises SharePoint servers to preserve specific values, enable Insane mode, and improve migration performance.
Index
Reasons to install the Server Extension
You need to preserve one of the values on this list.
You want to use Insane mode when migrating to SharePoint on-premises 2007, 2010, 2013, 2016, 2019, or SharePoint Server Subscription Edition (SE).
You're doing a migration that involves web front-end servers, and you want the best possible performance.
Checklist
Before installing the Server Extension, ensure that:
You have administrative rights on your SharePoint server.
The SharePoint server is .NET framework 3.5.
You read and understand the security considerations associated with the Server Extension.
To install the server extension, see Installation - Server Extension.
Note: You must install the Server extension on all your SharePoint web front-end servers, including where your Central administration is hosted, which could also be an app server.
Microsoft 365 considerations
The server extension cannot be installed in Microsoft 365. However, it is highly recommended to install the extension on your on-premises SharePoint servers when migrating to or from Microsoft 365.
Microsoft 365 to on-premises
When migrating from Microsoft 365 to an on-premises destination, the extension can help to maintain specific values and allows you to use Insane mode.
On-premises to Microsoft 365
When migrating from an on-premises source to Microsoft 365, the extension can help to maintain specific values and will help package your information. Packaging your information can improve migration performance, which can reduce the strain on Microsoft 365 and potentially lower throttling.
Notes: The Server Extension is not compatible with SharePoint 2003.