We have a customer who is experiencing Time-outs in our .NET application which uses SQL Server as the backend. The table in question is the OrderLines table in a SQL Server Database that has 4155151 rows Lately, the customer has reported, that intermittently they would get these Time-Outs during the process of updating this table. The code doesn't have a specific Time-out set in the Connection String to the Database but on the SQL Server, the Time-out is set to 10 minutes. The error reported is as follows: > Execution Timeout Expired. The timeout period elapsed prior to > completion of the operation or the server is not responding. > at > System.Data.Common.DbDataAdapter.UpdatedRowStatusErrors(RowUpdatedEventArgs > rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount) > <br/>at > System.Data.Common.DbDataAdapter.UpdatedRowStatus(RowUpdatedEventArgs > rowUpdatedEvent, BatchCommandInfo[] batchCommands, Int32 commandCount) > <br/> at System.Data.Common.DbDataAdapter.Update(DataRow[] dataRows, > DataTableMapping tableMapping) at > System.Data.Common.DbDataAdapter.UpdateFromDataTable(DataTable > dataTable, DataTableMapping tableMapping) at > System.Data.Common.DbDataAdapter.Update(DataTable dataTable) We have checked the Indexes for this table and it seems ok (see image attached). The customers IT guys have checked processes/tasks running on the server throughout the day, and did mention they recently updated to .NET 4.6.1 . Also, they mentioned they have plenty of RAM allocated and disk latency is fine and CPU is fine as well. Any ideas on how to trouble shoot this issue further? [![Stats for Customer Order Line Table Indexes][1]][1] [1]: https://i.sstatic.net/wqMjd.png