After being forced to signup for a Postman account even though Scratchpad worked fine, I did the Migrate Data and it shows all my Collections, however, they’re all empty. No URL, data, nothing - just the folder and name of the request seems to have been migrated. What am I missing?
Take a look here, it worked for me:
Postman Lightweight API Client Upgrade - 
General Discussion - Postman Community
Closed due to the reference to a different topic containing the solution.