title: Cannot Open DataFile SSIS Package via SSMS
body: <p><strong>Background</strong>
  Created package in BIDS.
  Deployed to SSMS
  Package writes files to a CSV file in a network fileserver.
  The default name of the package's flat file destination is $path\workcsvout.csv
  Package derives filename from an expression</p>
  
  <p><strong>Issue</strong>
  When I configure and run from SSMS, it fails with Error DFT -Extract to File:Error:Cannot open the datafile "........\DerivedFilename.</p>
  
  <p><strong>Troubleshooting</strong></p>
  
  <p>Verified the file exists in directory - used flat file destination temp filename, before derived filename - still failed
  changed name to file it was trying to open - still failed</p>
  
  <p>I am running job from my login in SSMS, via SSISDB - Projects - Package - .dtsx package - Execute </p>
  
  <p>See pictures below and advise if more information is needed.<a href="https://i.stack.imgur.com/Y0hIe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Y0hIe.png" alt="error1"></a>
  <a href="https://i.stack.imgur.com/6tfp6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6tfp6.png" alt="flatfiledestination"></a>
  Thanks</p>