Free: Contests & Raffles.
The last they build their boots off of tend to be more suited for people who have a wider heel. A different insole with more volume may move your foot high enough in the boot to tighten everything up and prevent this.
I haven't had a blister in 10 years probably, until these new Kenetreks. Both heels were torched after about 2 miles of steady incline. Maybe I will just tape up the heels and work at breaking them in on a flat surface along with some different inserts. I typically can hike all day, but those blister sure make you reconsider quickly.