diff --git a/flake.nix b/flake.nix
index abc614c8d..0233962b4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -250,6 +250,7 @@
             }
             ''
               cp ${installerClosureInfo}/registration $TMPDIR/reginfo
+              cp ${./scripts/create-darwin-volume.sh} $TMPDIR/create-darwin-volume.sh
               substitute ${./scripts/install-nix-from-closure.sh} $TMPDIR/install \
                 --subst-var-by nix ${nix} \
                 --subst-var-by cacert ${cacert}
@@ -268,6 +269,7 @@
                 # SC1090: Don't worry about not being able to find
                 #         $nix/etc/profile.d/nix.sh
                 shellcheck --exclude SC1090 $TMPDIR/install
+                shellcheck $TMPDIR/create-darwin-volume.sh
                 shellcheck $TMPDIR/install-darwin-multi-user.sh
                 shellcheck $TMPDIR/install-systemd-multi-user.sh
 
@@ -283,6 +285,7 @@
               fi
 
               chmod +x $TMPDIR/install
+              chmod +x $TMPDIR/create-darwin-volume.sh
               chmod +x $TMPDIR/install-darwin-multi-user.sh
               chmod +x $TMPDIR/install-systemd-multi-user.sh
               chmod +x $TMPDIR/install-multi-user
@@ -295,11 +298,15 @@
                 --absolute-names \
                 --hard-dereference \
                 --transform "s,$TMPDIR/install,$dir/install," \
+                --transform "s,$TMPDIR/create-darwin-volume.sh,$dir/create-darwin-volume.sh," \
                 --transform "s,$TMPDIR/reginfo,$dir/.reginfo," \
                 --transform "s,$NIX_STORE,$dir/store,S" \
-                $TMPDIR/install $TMPDIR/install-darwin-multi-user.sh \
+                $TMPDIR/install \
+                $TMPDIR/create-darwin-volume.sh \
+                $TMPDIR/install-darwin-multi-user.sh \
                 $TMPDIR/install-systemd-multi-user.sh \
-                $TMPDIR/install-multi-user $TMPDIR/reginfo \
+                $TMPDIR/install-multi-user \
+                $TMPDIR/reginfo \
                 $(cat ${installerClosureInfo}/store-paths)
             '');
 
diff --git a/scripts/create-darwin-volume.sh b/scripts/create-darwin-volume.sh
index dac30d72d..32fa577a8 100755
--- a/scripts/create-darwin-volume.sh
+++ b/scripts/create-darwin-volume.sh
@@ -5,42 +5,13 @@ root_disk() {
     diskutil info -plist /
 }
 
-apfs_volumes_for() {
-    disk=$1
-    diskutil apfs list -plist "$disk"
-}
-
-disk_identifier() {
-    xpath "/plist/dict/key[text()='ParentWholeDisk']/following-sibling::string[1]/text()" 2>/dev/null
-}
-
-volume_list_true() {
-    key=$1
-    xpath "/plist/dict/array/dict/key[text()='Volumes']/following-sibling::array/dict/key[text()='$key']/following-sibling::true[1]" 2> /dev/null
-}
-
-volume_get_string() {
-    key=$1 i=$2
-    xpath "/plist/dict/array/dict/key[text()='Volumes']/following-sibling::array/dict[$i]/key[text()='$key']/following-sibling::string[1]/text()" 2> /dev/null
+# i.e., "disk1"
+root_disk_identifier() {
+    diskutil info -plist / | xmllint --xpath "/plist/dict/key[text()='ParentWholeDisk']/following-sibling::string[1]/text()" -
 }
 
 find_nix_volume() {
-    disk=$1
-    i=1
-    volumes=$(apfs_volumes_for "$disk")
-    while true; do
-        name=$(echo "$volumes" | volume_get_string "Name" "$i")
-        if [ -z "$name" ]; then
-            break
-        fi
-        case "$name" in
-            [Nn]ix*)
-                echo "$name"
-                break
-                ;;
-        esac
-        i=$((i+1))
-    done
+    diskutil apfs list -plist "$1" | xmllint --xpath "(/plist/dict/array/dict/key[text()='Volumes']/following-sibling::array/dict/key[text()='Name']/following-sibling::string[starts-with(translate(text(),'N','n'),'nix')]/text())[1]" - 2>/dev/null || true
 }
 
 test_fstab() {
@@ -55,6 +26,20 @@ test_synthetic_conf() {
     grep -q "^nix$" /etc/synthetic.conf 2>/dev/null
 }
 
+# Create the paths defined in synthetic.conf, saving us a reboot.
+create_synthetic_objects(){
+    # Big Sur takes away the -B flag we were using and replaces it
+    # with a -t flag that appears to do the same thing (but they
+    # don't behave exactly the same way in terms of return values).
+    # This feels a little dirty, but as far as I can tell the
+    # simplest way to get the right one is to just throw away stderr
+    # and call both... :]
+    {
+        /System/Library/Filesystems/apfs.fs/Contents/Resources/apfs.util -t || true # Big Sur
+        /System/Library/Filesystems/apfs.fs/Contents/Resources/apfs.util -B || true # Catalina
+    } >/dev/null 2>&1
+}
+
 test_nix() {
     test -d "/nix"
 }
@@ -89,9 +74,7 @@ test_t2_chip_present(){
 }
 
 test_filevault_in_use() {
-    disk=$1
-    #      list vols on disk | get value of Filevault key | value is true
-    apfs_volumes_for "$disk" | volume_list_true FileVault | grep -q true
+    fdesetup isactive >/dev/null
 }
 
 # use after error msg for conditions we don't understand
@@ -132,7 +115,7 @@ main() {
 
     if ! test_nix; then
         echo "Creating mountpoint for /nix..." >&2
-        /System/Library/Filesystems/apfs.fs/Contents/Resources/apfs.util -B || true
+        create_synthetic_objects # the ones we defined in synthetic.conf
         if ! test_nix; then
             sudo mkdir -p /nix 2>/dev/null || true
         fi
@@ -143,12 +126,12 @@ main() {
         fi
     fi
 
-    disk=$(root_disk | disk_identifier)
+    disk="$(root_disk_identifier)"
     volume=$(find_nix_volume "$disk")
     if [ -z "$volume" ]; then
         echo "Creating a Nix Store volume..." >&2
 
-        if test_filevault_in_use "$disk"; then
+        if test_filevault_in_use; then
             # TODO: Not sure if it's in-scope now, but `diskutil apfs list`
             # shows both filevault and encrypted at rest status, and it
             # may be the more semantic way to test for this? It'll show
@@ -178,6 +161,7 @@ main() {
     if ! test_fstab; then
         echo "Configuring /etc/fstab..." >&2
         label=$(echo "$volume" | sed 's/ /\\040/g')
+        # shellcheck disable=SC2209
         printf "\$a\nLABEL=%s /nix apfs rw,nobrowse\n.\nwq\n" "$label" | EDITOR=ed sudo vifs
     fi
 }
diff --git a/scripts/install-darwin-multi-user.sh b/scripts/install-darwin-multi-user.sh
index 49076bd5c..a27be2a43 100644
--- a/scripts/install-darwin-multi-user.sh
+++ b/scripts/install-darwin-multi-user.sh
@@ -37,6 +37,13 @@ poly_service_setup_note() {
 EOF
 }
 
+poly_extra_try_me_commands(){
+  :
+}
+poly_extra_setup_instructions(){
+  :
+}
+
 poly_configure_nix_daemon_service() {
     _sudo "to set up the nix-daemon as a LaunchDaemon" \
           cp -f "/nix/var/nix/profiles/default$PLIST_DEST" "$PLIST_DEST"
diff --git a/scripts/install-multi-user.sh b/scripts/install-multi-user.sh
index e5cc4d7ed..5e8b4ac18 100644
--- a/scripts/install-multi-user.sh
+++ b/scripts/install-multi-user.sh
@@ -71,11 +71,9 @@ uninstall_directions() {
     subheader "Uninstalling nix:"
     local step=0
 
-    if [ -e /run/systemd/system ] && poly_service_installed_check; then
+    if poly_service_installed_check; then
         step=$((step + 1))
         poly_service_uninstall_directions "$step"
-    else
-        step=$((step + 1))
     fi
 
     for profile_target in "${PROFILE_TARGETS[@]}"; do
@@ -255,40 +253,20 @@ function finish_success {
         echo "To try again later, run \"sudo -i nix-channel --update nixpkgs\"."
     fi
 
-    if [ -e /run/systemd/system ]; then
-        cat <<EOF
+    cat <<EOF
 
 Before Nix will work in your existing shells, you'll need to close
 them and open them again. Other than that, you should be ready to go.
 
 Try it! Open a new terminal, and type:
-
+$(poly_extra_try_me_commands)
   $ nix-shell -p nix-info --run "nix-info -m"
-
+$(poly_extra_setup_instructions)
 Thank you for using this installer. If you have any feedback, don't
 hesitate:
 
 $(contactme)
 EOF
-    else
-        cat <<EOF
-
-Before Nix will work in your existing shells, you'll need to close
-them and open them again. Other than that, you should be ready to go.
-
-Try it! Open a new terminal, and type:
-
-  $ sudo nix-daemon
-  $ nix-shell -p nix-info --run "nix-info -m"
-
-Additionally, you may want to add nix-daemon to your init-system.
-
-Thank you for using this installer. If you have any feedback, don't
-hesitate:
-
-$(contactme)
-EOF
-   fi
 
 }
 
@@ -630,24 +608,20 @@ EOF
 }
 
 configure_shell_profile() {
-    # If there is an /etc/profile.d directory, we want to ensure there
-    # is a nix.sh within it, so we can use the following loop to add
-    # the source lines to it. Note that I'm _not_ adding the source
-    # lines here, because we want to be using the regular machinery.
-    #
-    # If we go around that machinery, it becomes more complicated and
-    # adds complications to the uninstall instruction generator and
-    # old instruction sniffer as well.
-    if [ -d /etc/profile.d ]; then
-        _sudo "create a stub /etc/profile.d/nix.sh which will be updated" \
-              touch /etc/profile.d/nix.sh
-    fi
-
     for profile_target in "${PROFILE_TARGETS[@]}"; do
         if [ -e "$profile_target" ]; then
             _sudo "to back up your current $profile_target to $profile_target$PROFILE_BACKUP_SUFFIX" \
                   cp "$profile_target" "$profile_target$PROFILE_BACKUP_SUFFIX"
+        else
+            # try to create the file if its directory exists
+            target_dir="$(dirname "$profile_target")"
+            if [ -d "$target_dir" ]; then
+                _sudo "to create a stub $profile_target which will be updated" \
+                    touch "$profile_target"
+            fi
+        fi
 
+        if [ -e "$profile_target" ]; then
             shell_source_lines \
                 | _sudo "extend your $profile_target with nix-daemon settings" \
                         tee -a "$profile_target"
@@ -725,9 +699,7 @@ main() {
     setup_default_profile
     place_nix_configuration
 
-    if [ -e /run/systemd/system ]; then
-        poly_configure_nix_daemon_service
-    fi
+    poly_configure_nix_daemon_service
 
     trap finish_success EXIT
 }
diff --git a/scripts/install-nix-from-closure.sh b/scripts/install-nix-from-closure.sh
index 14fb91534..2de41a6a4 100644
--- a/scripts/install-nix-from-closure.sh
+++ b/scripts/install-nix-from-closure.sh
@@ -26,9 +26,20 @@ fi
 
 # macOS support for 10.12.6 or higher
 if [ "$(uname -s)" = "Darwin" ]; then
-    macos_major=$(sw_vers -productVersion | cut -d '.' -f 2)
-    macos_minor=$(sw_vers -productVersion | cut -d '.' -f 3)
-    if [ "$macos_major" -lt 12 ] || { [ "$macos_major" -eq 12 ] && [ "$macos_minor" -lt 6 ]; }; then
+    IFS='.' read macos_major macos_minor macos_patch << EOF
+$(sw_vers -productVersion)
+EOF
+    # TODO: this is a temporary speed-bump to keep people from naively installing Nix
+    # on macOS Big Sur (11.0+, 10.16+) until nixpkgs updates are ready for them.
+    # *Ideally* this is gone before next Nix release. If you're intentionally working on
+    # Nix + Big Sur, just comment out this block and be on your way :)
+    if [ "$macos_major" -gt 10 ] || { [ "$macos_major" -eq 10 ] && [ "$macos_minor" -gt 15 ]; }; then
+        echo "$0: nixpkgs isn't quite ready to support macOS $(sw_vers -productVersion) yet"
+        exit 1
+    fi
+
+    if [ "$macos_major" -lt 10 ] || { [ "$macos_major" -eq 10 ] && [ "$macos_minor" -lt 12 ]; } || { [ "$macos_minor" -eq 12 ] && [ "$macos_patch" -lt 6 ]; }; then
+        # patch may not be present; command substitution for simplicity
         echo "$0: macOS $(sw_vers -productVersion) is not supported, upgrade to 10.12.6 or higher"
         exit 1
     fi
@@ -90,7 +101,7 @@ while [ $# -gt 0 ]; do
             ) >&2
 
             # darwin and Catalina+
-            if [ "$(uname -s)" = "Darwin" ] && [ "$macos_major" -gt 14 ]; then
+            if [ "$(uname -s)" = "Darwin" ] && { [ "$macos_major" -gt 10 ] || { [ "$macos_major" -eq 10 ] && [ "$macos_minor" -gt 14 ]; }; }; then
                 (
                     echo " --darwin-use-unencrypted-nix-store-volume: Create an APFS volume for the Nix"
                     echo "              store and mount it at /nix. This is the recommended way to create"
@@ -110,8 +121,8 @@ if [ "$(uname -s)" = "Darwin" ]; then
         "$self/create-darwin-volume.sh"
     fi
 
-    info=$(diskutil info -plist / | xpath "/plist/dict/key[text()='Writable']/following-sibling::true[1]" 2> /dev/null)
-    if ! [ -e $dest ] && [ -n "$info" ] && [ "$macos_major" -gt 14 ]; then
+    writable="$(diskutil info -plist / | xmllint --xpath "name(/plist/dict/key[text()='Writable']/following-sibling::*[1])" -)"
+    if ! [ -e $dest ] && [ "$writable" = "false" ]; then
         (
             echo ""
             echo "Installing on macOS >=10.15 requires relocating the store to an apfs volume."
diff --git a/scripts/install-systemd-multi-user.sh b/scripts/install-systemd-multi-user.sh
index e0201d53b..fda5ef600 100755
--- a/scripts/install-systemd-multi-user.sh
+++ b/scripts/install-systemd-multi-user.sh
@@ -72,24 +72,45 @@ poly_service_setup_note() {
 EOF
 }
 
+poly_extra_try_me_commands(){
+    if [ -e /run/systemd/system ]; then
+        :
+    else
+        cat <<EOF
+  $ sudo nix-daemon
+EOF
+    fi
+}
+poly_extra_setup_instructions(){
+    if [ -e /run/systemd/system ]; then
+        :
+    else
+        cat <<EOF
+Additionally, you may want to add nix-daemon to your init-system.
+
+EOF
+    fi
+}
+
 poly_configure_nix_daemon_service() {
-    _sudo "to set up the nix-daemon service" \
-          systemctl link "/nix/var/nix/profiles/default$SERVICE_SRC"
+    if [ -e /run/systemd/system ]; then
+        _sudo "to set up the nix-daemon service" \
+              systemctl link "/nix/var/nix/profiles/default$SERVICE_SRC"
 
-    _sudo "to set up the nix-daemon socket service" \
-          systemctl enable "/nix/var/nix/profiles/default$SOCKET_SRC"
+        _sudo "to set up the nix-daemon socket service" \
+              systemctl enable "/nix/var/nix/profiles/default$SOCKET_SRC"
 
-    handle_network_proxy
+        handle_network_proxy
 
-    _sudo "to load the systemd unit for nix-daemon" \
-          systemctl daemon-reload
+        _sudo "to load the systemd unit for nix-daemon" \
+              systemctl daemon-reload
 
-    _sudo "to start the nix-daemon.socket" \
-          systemctl start nix-daemon.socket
-
-    _sudo "to start the nix-daemon.service" \
-          systemctl restart nix-daemon.service
+        _sudo "to start the nix-daemon.socket" \
+              systemctl start nix-daemon.socket
 
+        _sudo "to start the nix-daemon.service" \
+              systemctl restart nix-daemon.service
+    fi
 }
 
 poly_group_exists() {