diff --git a/src/applications/herald/controller/HeraldRuleController.php b/src/applications/herald/controller/HeraldRuleController.php
index ce7a46cd00..37a583c7ef 100644
--- a/src/applications/herald/controller/HeraldRuleController.php
+++ b/src/applications/herald/controller/HeraldRuleController.php
@@ -24,6 +24,8 @@ final class HeraldRuleController extends HeraldController {
       }
       $cancel_uri = $this->getApplicationURI("rule/{$id}/");
     } else {
+      $new_uri = $this->getApplicationURI('new/');
+
       $rule = new HeraldRule();
       $rule->setAuthorPHID($viewer->getPHID());
       $rule->setMustMatchAll(1);
@@ -33,18 +35,40 @@ final class HeraldRuleController extends HeraldController {
 
       $rule_type = $request->getStr('rule_type');
       if (!isset($rule_type_map[$rule_type])) {
-        $rule_type = HeraldRuleTypeConfig::RULE_TYPE_PERSONAL;
+        return $this->newDialog()
+          ->setTitle(pht('Invalid Rule Type'))
+          ->appendParagraph(
+            pht(
+              'The selected rule type ("%s") is not recognized by Herald.',
+              $rule_type))
+          ->addCancelButton($new_uri);
       }
       $rule->setRuleType($rule_type);
 
-      $adapter = HeraldAdapter::getAdapterForContentType(
-        $rule->getContentType());
+      try {
+        $adapter = HeraldAdapter::getAdapterForContentType(
+          $rule->getContentType());
+      } catch (Exception $ex) {
+        return $this->newDialog()
+          ->setTitle(pht('Invalid Content Type'))
+          ->appendParagraph(
+            pht(
+              'The selected content type ("%s") is not recognized by '.
+              'Herald.',
+              $rule->getContentType()))
+          ->addCancelButton($new_uri);
+      }
 
       if (!$adapter->supportsRuleType($rule->getRuleType())) {
-        throw new Exception(
-          pht(
-            "This rule's content type does not support the selected rule ".
-            "type."));
+        return $this->newDialog()
+          ->setTitle(pht('Rule/Content Mismatch'))
+          ->appendParagraph(
+            pht(
+              'The selected rule type ("%s") is not supported by the selected '.
+              'content type ("%s").',
+              $rule->getRuleType(),
+              $rule->getContentType()))
+          ->addCancelButton($new_uri);
       }
 
       if ($rule->isObjectRule()) {