My 30-day trial expired yesterday and I registered for free. The process seemed to be going just fine (fill in the requested data, click on the 'Verify my email' button, login on my account on the web) but Sourcetree is permanently stuck 'Downloading a license'.
I tried looking for a license in my Atlassian account to no avail. Also cheched the forums but all I could find were old posts that redirect to pages that don't work anymore.
I think this might be a recent problem with the program since everyone I know who used SourceTree before never had this problem.