[root@nix:/home/USER]# tail -15 /etc/nixos/configuration.nix
  fileSystems."/mnt/hgfs" = {
    device = ".host:/";
    fsType = "vmhgfs";
    options = [
      "rw"
      "nosuid"
      "nodev"
      "nofail"
      "relatime"
      "ttl=5"
      "uid=USER"
      "gid=USER"
    ];
  };
}


[root@nix:/home/USER]# nixos-rebuild test
building Nix...
building the system configuration...
activating the configuration...
setting up /etc...
setting up tmpfiles
warning: the following units failed: mnt-hgfs.mount

● mnt-hgfs.mount - /mnt/hgfs
   Loaded: loaded (/etc/fstab; generated)
   Active: failed (Result: exit-code) since Mon 2018-09-17 22:33:29 CEST; 24ms ago
    Where: /mnt/hgfs
     What: .host:/
     Docs: man:fstab(5)
           man:systemd-fstab-generator(8)
  Process: 2804 ExecMount=/nix/store/d49n6q7b197j2nsnbdvn6i55rsnmiyq1-util-linux-2.31.1-bin/bin/mount .host:/ /mnt/hgfs -t vmhgfs -o rw,nosuid,nodev,relatime,ttl=5,uid=USER,gid=USER (code=exited, status=1/FAILURE)

Sep 17 22:33:29 nix systemd[1]: Mounting /mnt/hgfs...
Sep 17 22:33:29 nix mount[2804]: Error: cannot mount filesystem: No such device
Sep 17 22:33:29 nix systemd[1]: mnt-hgfs.mount: Mount process exited, code=exited status=1
Sep 17 22:33:29 nix systemd[1]: mnt-hgfs.mount: Failed with result 'exit-code'.
Sep 17 22:33:29 nix systemd[1]: Failed to mount /mnt/hgfs.
warning: error(s) occurred while switching to the new configuration


[root@nix:/home/USER]# /nix/store/d49n6q7b197j2nsnbdvn6i55rsnmiyq1-util-linux-2.31.1-bin/bin/mount .host:/ /mnt/hgfs -t vmhgfs
Error: cannot mount filesystem: No such device


[root@nix:/home/USER]# /nix/store/d49n6q7b197j2nsnbdvn6i55rsnmiyq1-util-linux-2.31.1-bin/bin/mount -t vmhgfs .host:/ /mnt/hgfs
Error: cannot mount filesystem: No such device


[root@nix:/home/USER]# mount | grep hgfs


[root@nix:/home/USER]# vmhgfs-fuse .host:/ /mnt/hgfs


[root@nix:/home/USER]# mount | grep hgfs
vmhgfs-fuse on /mnt/hgfs type fuse.vmhgfs-fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0)