There are many blogs on this topic - check this one medium.com/the-sixt-india-blog/preventing-your-emails-to-go-to-the-spam-folders-using-ip-warming-with-marketing-cloud-509dff9b5f43

Filtered DE gets created when you do a filter segmentation manually in Email studio. Lets say u want this filtering to be automated daily and refreshed - then you can create a Filter Activity in which you need to specify a Data filter. The Filter Activity is used within Automation Studio and u can schedule it to run on specifc days / time

You can add a script activity at the end of the workflow to invoke and start the next automation - use Wsproxy to invoke the automation object

Pls check the Import Activity video on my channel for the scenario you are mentioning. If the file is not compressed or encrypted, then you dont need to use File Transfer - u can directly use Import activity to read the csv file data into the DE. Ensure that you specify the folder you are going to search the source file from in your File Locations. In File Locations, you can configure sub folders or other root folders besides the default Import and Export folders on EFTP

I believe you need to enable attachments for email sends with support team and then configure in your email send

Please check this blog from Mateusz on Behavioral Triggers - mateuszdabrowski.pl/docs/config/sfmc-config-behavioral-triggers/

By default, the files are queued and processed in the order they have been dropped into the queue. You can read more about this in Greg's blog at gortonington.com/sfmc-file-drop-automations/ (check File Queueing heading)

In File drop activity you have check box called disable queuing 1. If you check that box current automation stops and starts the automation with new file. 2. By default it is unchecked this means It will follow queue, Once after completing the automation It will pick other file. Correct me Shibu If I’m wrong.

If it's grey then it means the activity has not been configured properly - please edit that step again and check if the configuration steps are completed properly including mapping of the fields. Please check this video for reference - kzfaq.info/get/bejne/fMWdhM5myMiWk3U.html

@@sfmctrailblazers Thanks for your answer. When I run Run Once - it works. How is it possible if it was completed in a proper way?

@@martinanovakova7328 It's difficult to answer without being able to see your screen and how you have set it up - have you set up the Entry source - I'm assuming you are using Scheduled (Run Once)? Do you only have one Import Activity step or any other additional steps in your workflow?

@@sfmctrailblazers I have Drop File activity (green) and File import activity (grey). My drop file activity is also 'Active'. It is really strange. If I test just only File Import activity (Run Once) - it works and file is imported.

Use Filedrop trigger which will trigger when the file is dropped - then in subsequent activities you can use one of the substitution strings to automatically select the file that triggered the automation without having to specify the filename directly - help.salesforce.com/s/articleView?id=sf.mc_as_substitution_strings_example.htm&type=5