We have a Exchange 2013 standard install with versin 15.0 Build 847.32 and we are having several errors: 

Watson report about to be sent for process id: 2864, with parameters: E12IIS, c-RTL-AMD64, 15.00.0847.032, M.E.RpcClientAccess.Service, M.E.RpcClientAccess.Parser, M.E.R.F.P.FastTransferContext`1.Process, System.IndexOutOfRangeException, 9700, 15.00.0847.030.

Watson report about to be sent for process id: 2864, with parameters: E12IIS, c-RTL-AMD64, 15.00.0847.032, M.E.RpcClientAccess.Service, M.E.RpcClientAccess.Parser, M.E.R.F.P.FastTransferContext`1.Process, System.IndexOutOfRangeException, 9700, 15.00.0847.030.ErrorReportingEnabled: False 

Watson report about to be sent for process id: 2864, with parameters: E12IIS, c-RTL-AMD64, 15.00.0847.032, M.E.RpcClientAccess.Service, unknown, M.E.D.T.I.F.F.TextStore.AddText, System.IndexOutOfRangeException, a89e, unknown.ErrorReportingEnabled: False 

We are trying found some solution but without Sucess, any contribution will be received.

Regards.

Hello

tip: https://support.microsoft.com/en-us/kb/2958036

Hi,

Is there any other error logs in Event viewer? Any influence in Client side? Please provide more information for further analysis.

Additionally, we can update your Exchange 2013 with the latest version package to have a try:
https://support.microsoft.com/en-us/kb/3030080

Regards,

I've upgraded to CU8 and the error persists.

Watson report about to be sent for process id: 5972, with parameters: E12IIS, c-RTL-AMD64, 15.00.1076.009, M.E.RpcClientAccess.Service, unknown, M.E.D.T.I.F.F.TextStore.AddText,

System.IndexOutOfRangeException, 6ace, unknown. ErrorReportingEnabled: False

Watson report about to be sent for process id: 5972, with parameters: E12IIS, c-RTL-AMD64, 15.00.1076.009, M.E.RpcClientAccess.Service, unknown, M.E.D.T.I.F.F.TextStore.AddText,

System.IndexOutOfRangeException, 5453, unknown. ErrorReportingEnabled: False

I can't identify lapto/desktop, the error doesn't offer me information on this, any idea more.

Many thanks to all. 

Are you using Symantec Enterprise Vault? We are seeing a similar issue. When we check our "C:\Program Files\Microsoft\Exchange Server\V15\Logging\RPC Client Access" folder and search the logs for IndexOutOfRangeExceptions we are seeing that they are associated to our Enterprise Vault service account.