MySQL cannot create foreign key, errors 1005, 150
I confused my databases and incorrectly thought I was working with InnoDB databases. Turns out one of them was MyISAM and then foreign keys don't work. Unfortunately, MySQL Workbench doesn't inform the user of this on Windows, but it does on the Macintosh version. (I guess it's good after all to have developers on your team with Macs.)

Hope this helps somebody with the same error message.