Hello Ludo, I don't have the error anymore since I've done "guix system build config.scm -k -no-substitutes". Before that, the error appeared several times with different packages (qtmultimedia, owncloud-client, ...). Thanks, ------------------ Olivier Farges (https://www.buzcard.com/VcardInformations.aspx?act=4IGzjjQsrHcXLYiipC8nBA==) Cliquez sur ma photo pour accéder à ma carte on-line complète et à jour. ------------------ 5 mai 2017 09:53 ludo@gnu.org (mailto:ludo@gnu.org) a écrit: Hello, "Olivier Farges" skribis: When I'm doing an update with guix system reconfigure, I have a strange error message "guix system: error: build failed: got unexpected path `/gnu/store/z8.......' from subsituter. Could you paste the complete error message? Thanks in advance! Ludo’.