Hi Maxim, > Judging from the above, it seems this issue has been resolved. grafting is still a performance issue imo. Compare for example: $ time guix environment --ad-hoc --search-paths r-learnr guix environment --ad-hoc --search-paths r-learnr 5,90s user 0,09s system 210% cpu 2,844 total $ time guix environment --ad-hoc --search-paths r-learnr --no-grafts guix environment --ad-hoc --search-paths r-learnr --no-grafts 2,03s user 0,08s system 164% cpu 1,277 total Cheers, Lars