--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/uinfo/inundationduration/YearChoice.java	Thu Jun 28 14:11:12 2018 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/uinfo/inundationduration/YearChoice.java	Thu Jun 28 15:10:04 2018 +0200
@@ -25,14 +25,14 @@
     protected LinkedHashMap<String, String> makeEntries(final CallMeta meta, final Artifact artifact) {
         // in helper-klasse; dann hier label lazy loaden
         final LinkedHashMap<String, String> entries = new LinkedHashMap<>();
-
-        final InundationDurationAccess access = new InundationDurationAccess((UINFOArtifact) artifact);
+        if (artifact != null) {// necessary; otherwise crashes randomly when reloading old calculations
+            final InundationDurationAccess access = new InundationDurationAccess((UINFOArtifact) artifact);
 
-        final UedauernPropertiesHelper helper = UedauernPropertiesHelper.getInstance(access.getRiverName());
-        final LinkedHashMap<String, String> extras = helper.getExtraLayers(meta);
-        entries.put("state.uinfo.year", null);
-        entries.putAll(extras);
-
+            final UedauernPropertiesHelper helper = UedauernPropertiesHelper.getInstance(access.getRiverName());
+            final LinkedHashMap<String, String> extras = helper.getExtraLayers(meta);
+            entries.put("state.uinfo.year", null);
+            entries.putAll(extras);
+        }
         return entries;
     }