diff --git a/usr/share/orange-yourdev-login/login-password b/usr/share/orange-yourdev-login/login-password
index 6362c8f..d16d17d 100755
--- a/usr/share/orange-yourdev-login/login-password
+++ b/usr/share/orange-yourdev-login/login-password
@@ -6,11 +6,17 @@
 
 (( EUID == 0 )) || { echo >&2 "Not root." ; exit 1 ; }
 
-update-alternatives --set gdm-smartcard /etc/pam.d/gdm-smartcard-sssd-or-password
-sed -Ei 's/(enable-smartcard-authentication)=.*/\1=false/' /etc/dconf/db/gdm.d/03-smartcard
+if [ -e /etc/pam.d/gdm-smartcard-sssd-or-password ] ; then
+    update-alternatives --set gdm-smartcard \
+        /etc/pam.d/gdm-smartcard-sssd-or-password
+fi
+
+sed -Ei 's/(enable-smartcard-authentication)=.*/\1=false/' \
+    /etc/dconf/db/gdm.d/03-smartcard
 dconf update
+
 systemctl enable sssd.service sssd-pam.socket
-systemctl start sssd.service
+systemctl start sssd.service || exit 1
 
 cat << EOF
 Please restart desktop manager with command:
diff --git a/usr/share/orange-yourdev-login/login-pki b/usr/share/orange-yourdev-login/login-pki
index 9598191..062b517 100755
--- a/usr/share/orange-yourdev-login/login-pki
+++ b/usr/share/orange-yourdev-login/login-pki
@@ -6,8 +6,12 @@
 
 (( EUID == 0 )) || { echo >&2 "Not root." ; exit 1 ; }
 
-update-alternatives --set gdm-smartcard /etc/pam.d/gdm-smartcard-pkcs11-exclusive
-sed -Ei 's/(enable-smartcard-authentication)=.*/\1=true/' /etc/dconf/db/gdm.d/03-smartcard
+update-alternatives --set gdm-smartcard \
+    /etc/pam.d/gdm-smartcard-pkcs11-exclusive \
+    || { echo >&2 "Cannot switch to PKI login (GDM too old?)" ; exit 1 ; }
+
+sed -Ei 's/(enable-smartcard-authentication)=.*/\1=true/' \
+    /etc/dconf/db/gdm.d/03-smartcard
 dconf update
 
 cat << EOF