When we desing the package it is required to create an error log file for reference if any error occured during the execution of package. Here the error log file is unique for every execution. OnError event will catch the error details if it ocure on package further by using Script task we can write these details on text/log file. to do this task we need to follow these steps: Create variables to provide he physical location of log file Write a script to log the error description on text file Step1: Creating Variable > ErrorLogPath (Type: String): That would be configured by configuration file externaly for example C:\App\Log\ > ErrorLogFile (Type: String): It is expression based. To set the expression select the variable -> Press F4 to see the property Set IsExpression=True and write the following code for expression: @[User::ErrorLogPath]+"PackageErrorLog"+"_"+(DT_WSTR, 4) DATEPART( "yyyy", @[System::StartTime]) +(DT_WSTR, 2) DATEPART( "mm...