Can't cancel the minification process

I'm going INSANE trying to work with Hummingbird. I started the minification/check files task, and I can't cancel it! I click cancel, it refreshes the page and pops up the same progress bar. sometimes it starts over, sometimes it resumes. even disabling the plugin doesn't have an effect - I can still access the minification page by its URL, and it's STILL RUNNING CHECK FILES! This is CRAZY.