diff --git a/rtgui/main.cc b/rtgui/main.cc
index ce212daf2..9548bb289 100644
--- a/rtgui/main.cc
+++ b/rtgui/main.cc
@@ -529,7 +529,7 @@ int main (int argc, char **argv)
         licensePath = Glib::build_filename (exePath, LICENCE_SEARCH_PATH);
     }
 
-    if (Glib::path_is_absolute (LENSFUN_DB_PATH)) {
+    if (strlen(LENSFUN_DB_PATH) == 0 || Glib::path_is_absolute (LENSFUN_DB_PATH)) {
         options.rtSettings.lensfunDbDirectory = LENSFUN_DB_PATH;
     } else {
         options.rtSettings.lensfunDbDirectory = Glib::build_filename (exePath, LENSFUN_DB_PATH);