When a package contains a directory in one of the systemd directories (like flatpak does), it is symlinked into the *-units derivation. Then later, the derivation will try to create the directory, which will fail: mkdir: cannot create directory '/nix/store/…-user-units/dbus.service.d': File exists builder for '/nix/store/…-user-units.drv' failed with exit code 1 Closes: #33233
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.