diff --git a/nixos/modules/installer/cd-dvd/installation-cd-base.nix b/nixos/modules/installer/cd-dvd/installation-cd-base.nix
index 1ed56386e6e7..298b8d88bb59 100644
--- a/nixos/modules/installer/cd-dvd/installation-cd-base.nix
+++ b/nixos/modules/installer/cd-dvd/installation-cd-base.nix
@@ -30,7 +30,7 @@ with lib;
   boot.loader.grub.memtest86.enable = true;
 
   # Allow the user to log in as root without a password.
-  users.extraUsers.root.initialHashedPassword = "";
+  users.users.root.initialHashedPassword = "";
 
   system.nixos.stateVersion = mkDefault "18.03";
 }
diff --git a/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix b/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
index ddf91a5656c7..4eb28434e192 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
@@ -34,7 +34,7 @@ in
   boot.kernelParams = ["cma=32M" "console=ttyS0,115200n8" "console=ttyAMA0,115200n8" "console=tty0"];
 
   # FIXME: this probably should be in installation-device.nix
-  users.extraUsers.root.initialHashedPassword = "";
+  users.users.root.initialHashedPassword = "";
 
   sdImage = {
     populateBootCommands = let
diff --git a/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix b/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix
index 891923234dda..0d595503f193 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix
@@ -35,7 +35,7 @@ in
   boot.kernelParams = ["console=ttyS0,115200n8" "console=ttymxc0,115200n8" "console=ttyAMA0,115200n8" "console=ttyO0,115200n8" "console=ttySAC2,115200n8" "console=tty0"];
 
   # FIXME: this probably should be in installation-device.nix
-  users.extraUsers.root.initialHashedPassword = "";
+  users.users.root.initialHashedPassword = "";
 
   sdImage = {
     populateBootCommands = let
diff --git a/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix b/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix
index fe6cc4161630..aa52844288ca 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix
@@ -28,7 +28,7 @@ in
   boot.kernelPackages = pkgs.linuxPackages_rpi;
 
   # FIXME: this probably should be in installation-device.nix
-  users.extraUsers.root.initialHashedPassword = "";
+  users.users.root.initialHashedPassword = "";
 
   sdImage = {
     populateBootCommands = let
diff --git a/nixos/modules/installer/netboot/netboot-base.nix b/nixos/modules/installer/netboot/netboot-base.nix
index b12eaccf8707..5e8f7f93d92a 100644
--- a/nixos/modules/installer/netboot/netboot-base.nix
+++ b/nixos/modules/installer/netboot/netboot-base.nix
@@ -16,5 +16,5 @@ with lib;
     ];
 
   # Allow the user to log in as root without a password.
-  users.extraUsers.root.initialHashedPassword = "";
+  users.users.root.initialHashedPassword = "";
 }
diff --git a/nixos/modules/installer/virtualbox-demo.nix b/nixos/modules/installer/virtualbox-demo.nix
index c40e30354206..f58c36587801 100644
--- a/nixos/modules/installer/virtualbox-demo.nix
+++ b/nixos/modules/installer/virtualbox-demo.nix
@@ -14,7 +14,7 @@ with lib;
   boot.loader.grub.fsIdentifier = "provided";
 
   # Allow mounting of shared folders.
-  users.extraUsers.demo.extraGroups = [ "vboxsf" ];
+  users.users.demo.extraGroups = [ "vboxsf" ];
 
   # Add some more video drivers to give X11 a shot at working in
   # VMware and QEMU.