Previously HeavySet would take CSV files exported from other apps and import their data. From version 2017.2 this is no longer the case.
The reason this function was removed is due to other apps export functions being broken, or inconsistent. Changes made to these formats or supporting additional formats required HeavySet app updates. This is not a scalable solution.
Runloop is still committed to allowing users to import data from other apps. The approach we are taking now is to let users convert their existing CSV files with our new CSV File Converter tool. This tool allows you to load in your existing CSV file, tell us what each column represents, then export a new HeavySet compatible CSV format which you can load into the app.