diff --git a/scripts/install b/scripts/install
index db105ea..5f72bf4 100644
--- a/scripts/install
+++ b/scripts/install
@@ -250,6 +250,12 @@ ynh_store_file_checksum --file="$final_path/htdocs/conf/conf.php"
 ynh_script_progression --message="Configuring permissions..." --weight=1
 
 # Set permissions on app files
+if [ ! -f $datadir/install.lock ]; then
+	echo 'This is a lock file to prevent use of install pages (set with permission 440)' > "$datadir/install.lock"
+	chown $app:$app "$datadir/install.lock"
+    chmod 440 "$datadir/install.lock"
+fi
+
 chmod 750 "$final_path"
 chmod -R o-rwx "$final_path"
 chown -R $app:www-data "$final_path"
diff --git a/scripts/upgrade b/scripts/upgrade
index cc68717..2d34b7d 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -303,6 +303,12 @@ ynh_use_logrotate --non-append
 ynh_script_progression --message="Configuring permissions..." --weight=1
 
 # Set permissions on app files
+if [ ! -f $datadir/install.lock ]; then
+	echo 'This is a lock file to prevent use of install pages (set with permission 440)' > "$datadir/install.lock"
+	chown $app:$app "$datadir/install.lock"
+    chmod 440 "$datadir/install.lock"
+fi
+
 chmod 750 "$final_path"
 chmod -R o-rwx "$final_path"
 chown -R $app:www-data "$final_path"