ADO.NET Failed to load msxmlsql.dll

How to fix this error?

   System.Data.SqlClient.SqlException: Failed to load msxmlsql.dll.
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior
cmdBehavior, RunBehavior runBehavior, Boolean returnStream)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()

am i missing something that needs to be installed on sql server? is this a
client side ado.net issue?

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