My Bitbucket account uses OAuth (since there's now no other option). Sourcetree has taken to asking me for my password, the credential helper store, etc. when I no longer use any of them. I've already followed all the steps from the "So you're using Windows and Sourcetree sucks" page. All except for wiping all of my details off the hard drive and reinstalling since I have a lot of connected accounts that I don't want to have to recreate.
Yesterday I was able to get connected by trying each of the options below in turn until one worked, but today none of them work. When I deleted the password file, Sourcetree immediately (not "eventually") asked me for the password, which I no longer use since it's OAuth, not username and password now. I was already using my Bitbucket username in the host address, not my email address.
Additionally, running
git fetch origin master
(what I was trying to do in Sourcetree) from the command line simply works.
I also can't use my computer while Sourcetree is running because it pops up the following prompt every three seconds.