diff --git a/Libraries/JavaScriptAppEngine/Initialization/ExceptionsManager.js b/Libraries/JavaScriptAppEngine/Initialization/ExceptionsManager.js
index 91afe2008..224ce0966 100644
--- a/Libraries/JavaScriptAppEngine/Initialization/ExceptionsManager.js
+++ b/Libraries/JavaScriptAppEngine/Initialization/ExceptionsManager.js
@@ -48,8 +48,10 @@ function reportException(e: Exception, isFatal: bool, stack?: any) {
           var prettyStack = parseErrorStack(e, map);
           RCTExceptionsManager.updateExceptionMessage(e.message, prettyStack);
         })
-        .then(null, error => {
-          console.error('#CLOWNTOWN (error while displaying error): ' + error.message);
+        .catch(error => {
+          // This can happen in a variety of normal situations, such as
+          // Network module not being available, or when running locally
+          console.warn('Unable to load source map: ' + error.message);
         });
     }
   }
diff --git a/Libraries/JavaScriptAppEngine/Initialization/loadSourceMap.js b/Libraries/JavaScriptAppEngine/Initialization/loadSourceMap.js
index a826db7bf..c3499ac9f 100644
--- a/Libraries/JavaScriptAppEngine/Initialization/loadSourceMap.js
+++ b/Libraries/JavaScriptAppEngine/Initialization/loadSourceMap.js
@@ -13,10 +13,13 @@
 'use strict';
 
 var Promise = require('Promise');
-var RCTSourceCode = require('NativeModules').SourceCode;
+var NativeModules = require('NativeModules');
 var SourceMapConsumer = require('SourceMap').SourceMapConsumer;
 var SourceMapURL = require('./source-map-url');
 
+var RCTSourceCode = NativeModules.SourceCode;
+var RCTDataManager = NativeModules.DataManager;
+
 function loadSourceMap(): Promise {
   return fetchSourceMap()
     .then(map => new SourceMapConsumer(map));
@@ -31,17 +34,31 @@ function fetchSourceMap(): Promise {
     return Promise.reject(new Error('RCTSourceCode module is not available'));
   }
 
+  if (!RCTDataManager) {
+    // Used internally by fetch
+    return Promise.reject(new Error('RCTDataManager module is not available'));
+  }
+
   return new Promise(RCTSourceCode.getScriptText)
     .then(extractSourceMapURL)
+    .then((url) => {
+      if (url === null) {
+        return Promise.reject(new Error('No source map URL found. May be running from bundled file.'));
+      }
+      return Promise.resolve(url);
+    })
     .then(fetch)
     .then(response => response.text())
 }
 
-function extractSourceMapURL({url, text, fullSourceMappingURL}): string {
+function extractSourceMapURL({url, text, fullSourceMappingURL}): ?string {
   if (fullSourceMappingURL) {
     return fullSourceMappingURL;
   }
   var mapURL = SourceMapURL.getFrom(text);
+  if (!mapURL) {
+    return null;
+  }
   var baseURL = url.match(/(.+:\/\/.*?)\//)[1];
   return baseURL + mapURL;
 }