Hi, Using Guix 55685e4, I get: --8<---------------cut here---------------start------------->8--- $ guix build -S --no-substitutes fossil The following derivations will be built: /gnu/store/0cb20s9w8l8jg7i1dnw2xw0j197cbhxq-fossil-src-2.11.tar.xz.drv /gnu/store/l6wr7qb60ahg4kslajr3rqk3limhvs0a-fossil-src-2.11.tar.gz.drv building /gnu/store/l6wr7qb60ahg4kslajr3rqk3limhvs0a-fossil-src-2.11.tar.gz.drv... Starting download of /gnu/store/pb5jmi9zalg6xylzsjmrskwxs0kar97l-fossil-src-2.11.tar.gz From https://www.fossil-scm.org/index.html/uv/fossil-src-2.11.tar.gz... following redirection to `https://fossil-scm.org/home/uv/fossil-src-2.11.tar.gz'... downloading from https://www.fossil-scm.org/index.html/uv/fossil-src-2.11.tar.gz ... sha256 hash mismatch for /gnu/store/pb5jmi9zalg6xylzsjmrskwxs0kar97l-fossil-src-2.11.tar.gz: expected hash: 0c9nzx42wxfmym9vf1pnbdb1c7gp7a7zqky60izxsph7w2xh8nix actual hash: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73 hash mismatch for store item '/gnu/store/pb5jmi9zalg6xylzsjmrskwxs0kar97l-fossil-src-2.11.tar.gz' build of /gnu/store/l6wr7qb60ahg4kslajr3rqk3limhvs0a-fossil-src-2.11.tar.gz.drv failed View build log at '/var/log/guix/drvs/l6/wr7qb60ahg4kslajr3rqk3limhvs0a-fossil-src-2.11.tar.gz.drv.bz2'. cannot build derivation `/gnu/store/0cb20s9w8l8jg7i1dnw2xw0j197cbhxq-fossil-src-2.11.tar.xz.drv': 1 dependencies couldn't be built guix build: error: build of `/gnu/store/0cb20s9w8l8jg7i1dnw2xw0j197cbhxq-fossil-src-2.11.tar.xz.drv' failed --8<---------------cut here---------------end--------------->8--- It is probably an upstream in-place replacement. All the best, simon