Error When trying to access listdata.svc: Could not load type ‘System.Data.Services.Providers.IDataServiceUpdateProvider’ from assembly ‘System.Data.Services, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’.

When trying to access: https://sharepoint.com/_vti_bin/listdata.svc , Received this Error message:

Error: 

Could not load type ‘System.Data.Services.Providers.IDataServiceUpdateProvider’ from assembly ‘System.Data.Services, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’.

Fix:

Install the ADO.NET Data Services Update for .NET Framework 3.5 SP1 – KB976127
https://support.microsoft.com/en-us/topic/description-of-the-ado-net-data-services-update-for-net-framework-3-5-sp1-for-windows-server-2003-windows-xp-windows-vista-and-windows-server-2008-may-7-2010-e525c2b3-249c-7d66-3cb2-c029c786c745