Hi, On Thu, 05 Nov 2020 at 17:59, Luis Felipe wrote: Therefore, it is nice improvement! :-) > real 0m56,245s > user 0m4,324s > sys 0m0,218s > real 0m43,272s > user 0m4,214s > sys 0m0,200s Because, I bet that most of the time is spent in the “time-machine” part. I mean, compare with: time guix time-machine --commit=$new -- help All the best, simon