File not triggering automation, but then exact same file when manually dropped does trigger automation? (Automation Studio, Marketing Cloud)

Question

I set up an automation that is triggered by a filedrop. When the file is dropped, it should be imported into a data extension. Also, when the automation runs, it kicks off a journey.

I've tested it multiple times and the filedrop has triggered the automation.

This morning, we went live and the filedrop did not trigger the automation. The automation was Active and waiting. The correct trigger file was in the correct directory with the correct naming pattern. I removed that trigger file from our FTP and then re-dropped the exact same file myself and the automation was triggered with no errors.

Has anyone experienced this? Is there potentially some problem with the way we are setting up the drop to the FTP?

Answer 1

Here is my theory. I assume you are utilising a filename suffix in your trigger filename pattern: New_Customer_Data_Report%%Day%%%%Month%%%%Year%%.csv

Some FTP integrations, especially when dealing with large files, tend to create a file with a different suffix while uploading the data (and while data is not complete) before renaming it to the right suffix. This temporary suffix can be, e.g. .part

Once the SFTP connection is initiated and the file starts uploading, the trigger "sees" a .part file, and will not trigger. If you remove the suffix from your filename pattern, the trigger should work fine.

When you set up the File Import Activity itself, you should use %%BASEFILENAME_FROM_TRIGGER%%.csv as the file arriving to the FTP has a .part suffix, until it has finished uploading from the external source. If you would use %%FILENAME_FROM_TRIGGER%% the import will fail, as it will be looking for TEST02.csv.part

You can find additional best practices for importing files on this page. Reference for file name patterns here. And my favourite: Substitution Strings Example.