diff --git a/scripts/install b/scripts/install
index af51f33..7129efe 100644
--- a/scripts/install
+++ b/scripts/install
@@ -40,7 +40,7 @@ install_jellyfin_packages
 #=================================================ç
 ynh_script_progression --message="Adding system configurations related to $app..." --weight=1
 
-if grep -q "^render:" /etc/group; then
+if getent group render && ! id -Gn "$app" | grep -qw "\brender\b" >/dev/null; then
 	# Add user to render group
 	adduser "$app" render
 fi
diff --git a/scripts/restore b/scripts/restore
index 73eff90..c0860b5 100644
--- a/scripts/restore
+++ b/scripts/restore
@@ -19,7 +19,7 @@ ynh_script_progression --message="Reconfiguring the dedicated system user..." --
 
 # It could be created later by the deb, but it's cleaner here
 ynh_system_user_create --username=$app
-if grep -q "^render:" /etc/group; then
+if getent group render && ! id -Gn "$app" | grep -qw "\brender\b" >/dev/null; then
 	# Add user to render group
 	adduser $app render
 fi
diff --git a/scripts/upgrade b/scripts/upgrade
index 6ae5f92..30965d4 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -31,7 +31,7 @@ ynh_systemd_action --service_name="$app" --action="stop" --log_path="systemd" --
 ynh_script_progression --message="Ensuring downward compatibility..." --weight=1
 
 # If render group exists, and system user doesn't belong to it, add it
-if grep -q "^render:" /etc/group && ! id -Gn "$app" | grep -q '\brender\b'; then
+if getent group render && ! id -Gn "$app" | grep -qw "\brender\b" >/dev/null; then
 	adduser "$app" render
 fi