nvm, Filename field is what you need. no idea what Activity ID refers to! 

recognize this. Looking at the activityID's in the strava webGUI, thse are different than those in the bulk download. When I use an activityID from the bulk download I get to see an activity from another athlete than myself. So what do the numbers in the bulk download represent?

I understand the frustration with matching the Activity IDs in the activities.csv file to the raw .fit files. It can be tricky when the IDs don’t align. One approach might be to check if a separate mapping file links the IDs. On a different note, I’ve been using SketchUp Crackeado for some design projects, and it’s amazing how important accurate data is in any analysis. Good luck with your work!

O wow, I completely overlooked the activities.csv file in the default download folder. This is it. Big THX to you mate 😀👍

It seems like there's a mismatch between the "Activity ID" in the activities.csv file and the file names of the raw activity files (e.g. .fit.gz files). This could be due to different ID systems used by the platform for referencing activities in the CSV vs. raw file naming. To match them, you might need to look into metadata or timestamps within the raw files and cross-reference them with the corresponding entries in the CSV file. Some platforms store the Activity ID in the metadata of the .fit files, which can be extracted using specialized tools or libraries for .fit file parsing.