Applies to: SharePoint Foundation 2013, SharePoint Server 2013 Enterprise
When you run this cmdlet to add a user to the SharePoint_Shell_Access role, you must have membership in the securityadmin fixed server role on the SQL Server instance, membership in the db_owner fixed database role on all affected databases, and local administrative permission on the local computer.
This cmdlet is intended only to be used with a database that uses Windows authentication. There is no need to use this cmdlet for databases that use SQL authentication; in fact, doing so may result in an error message.
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