diff --git a/assets/themes/bag_import/bag.json b/assets/themes/bag_import/bag.json
index c4934eb7d..331163286 100644
--- a/assets/themes/bag_import/bag.json
+++ b/assets/themes/bag_import/bag.json
@@ -196,6 +196,18 @@
           "id": "Import button",
           "render": "{import_way_button(osm:buildings, building=$_bag_obj:building; ref:bag=$_bag_obj:ref:bag; source=BAG; source:date=$_bag_obj:source:date; start_date=$_bag_obj:start_date, Upload this building to OpenStreetMap)}",
           "mappings": [
+            {
+              "#": "Something went wrong calculating the tags - don't show an import button",
+              "if": {
+                "or": [
+                  "_bag_obj:building=",
+                  "_bag_obj:ref:bag"
+                ]
+              },
+              "then": {
+                "en": "Didn't calculate the correct values yet. Refresh this page"
+              }
+            },
             {
               "if": "_overlaps_with!=",
               "then": "{conflate_button(osm:buildings, building=$_bag_obj:building; ref:bag=$_bag_obj:ref:bag; source=BAG; source:date=$_bag_obj:source:date; start_date=$_bag_obj:start_date, Replace the geometry in OpenStreetMap, , _osm_obj:id)}"