In this article we will be seeing how to resolve the error "Could not load type 'System.Data.Services.Providers.IDataServiceUpdateProvider' from assembly 'System.Data.Services, Version=220.127.116.11, Culture=neutral, PublicKeyToken=b77a5c561934e089'".
When you try to access the SharePoint list using REST API through the URL http://servername:12345/_vti_bin/listdata.svc you may be getting the following error.
The reason for the error would be you may not have installed ADO.Net Data Services in your computer server.
ADO.Net Data Services:
For Windows Vista and Windows 2008 -http://www.microsoft.com/downloads/details.aspx?familyid=4B710B89-8576-46CF-A4BF-331A9306D555&displaylang=en
For Windows 7 and Windows 2008 R2 -http://www.microsoft.com/downloads/details.aspx?familyid=79d7f6f8-d6e9-4b8c-8640-17f89452148e&displaylang=en
Note: Download the files appropriate to you or else when you try to install you would be getting the following error.
Windows 2008 R2:
For Windows 2008 R2 select the following one
Install ADO. Net Data Services:
Open the downloaded file.
Windows Update Standalone Installer wizard will pop up.
Click on Yes.
Restart your server.
Now try to access the list using API, you would be able to access the list successfully.