diff --git a/polymod/Polymod.hx b/polymod/Polymod.hx
index de714ae3..e68689d7 100644
--- a/polymod/Polymod.hx
+++ b/polymod/Polymod.hx
@@ -1704,8 +1704,16 @@ class ModMetadata
     m.license = JsonHelp.str(json, 'license');
     m.metadata = JsonHelp.mapStr(json, 'metadata');
 
-    m.dependencies = JsonHelp.mapVersionRule(json, 'dependencies');
-    m.optionalDependencies = JsonHelp.mapVersionRule(json, 'optionalDependencies');
+    try
+    {
+      m.dependencies = JsonHelp.mapVersionRule(json, 'dependencies');
+      m.optionalDependencies = JsonHelp.mapVersionRule(json, 'optionalDependencies');
+    }
+    catch (msg:Dynamic)
+    {
+      Polymod.error(MOD_METADATA_PARSE_FAILED, 'Error parsing mod dependencies from metadata: ${msg}', origin);
+      return null;
+    }
 
     return m;
   }
diff --git a/polymod/format/JsonHelp.hx b/polymod/format/JsonHelp.hx
index 9bc01235..65a99fe2 100644
--- a/polymod/format/JsonHelp.hx
+++ b/polymod/format/JsonHelp.hx
@@ -69,7 +69,8 @@ class JsonHelp
     {
       for (field in Reflect.fields(val))
       {
-        var fieldVal = Reflect.field(val, field);
+        var fieldVal:Null<String> = Reflect.field(val, field);
+        if (fieldVal == null || StringTools.trim(fieldVal) == '') fieldVal = '*';
         map.set(field, VersionRule.stringToVersionRule(fieldVal));
       }
     }