Product:
Cognos Controller 10.3.1
Microsoft Windows 2012 R2 Server

Issue:
An error occurred while trying to access the server when you start the Cognos Controller client and try to login.

Error message:
System.Web.Services.Protocols.SoapException: Server was unable to process request. —> System.ArgumentException: Requested registry access is not allowed.

at Microsoft.VisualBasic.ErrObject.Raise(Int32 Number, Object Source, Object Description, Object HelpFile, Object HelpContext)

at ControllerServerCommon.RaiseErrSrv.RaiseError(String sUser, Int32 lErrNo, String sErrSource, String sErrDesc, String sErrHelpFile, Int32 lErrHelpContext)

at FrServerB.LocalConnectionBusiness.SetSelectDb(String sGuid, String sUser, Boolean bSelectDb)

at FrServerB.ConnectionBusiness.SetSelectDb(String sGuid, String sUser, Boolean bSelectDb)

— End of inner exception stack trace —

at Microsoft.VisualBasic.ErrObject.Raise(Int32 Number, Object Source, Object Description, Object HelpFile, Object HelpContext)

at Cognos.Controller.Common.RaiseErrCli.RaiseError(Int32 lErrNo, String sErrSource, String sErrDesc, String sErrHelpFile, Int32 lErrHelpContext)

at Cognos.Controller.Direct.ConnectionDirect.SetSelectDb(Boolean bSelectDb)

at CCR.AppContext.SelectDb()

at CCR.AppContext.Login()

Solution:
In the IIS manager change the user account used by the Application pool that Controllerserver is using.

Start Internet Information Servers Manager
Go to Application pools
Select NET v4.5
Click on Advance Settings
Change Application pool identity to LocalSystem from ApplicationPoolIdentity
Click OK
Restart IIS services.

More information:
http://www-01.ibm.com/support/docview.wss?uid=swg21691747