diff --git a/android/app/src/main/java/com/microsoft/codepush/react/CodePushPackage.java b/android/app/src/main/java/com/microsoft/codepush/react/CodePushPackage.java
index a9483b4..dc8218e 100644
--- a/android/app/src/main/java/com/microsoft/codepush/react/CodePushPackage.java
+++ b/android/app/src/main/java/com/microsoft/codepush/react/CodePushPackage.java
@@ -246,7 +246,7 @@ public class CodePushPackage {
             String relativeBundlePath = CodePushUpdateUtils.findJSBundleInUpdateContents(newUpdateFolderPath, expectedBundleFileName);
 
             if (relativeBundlePath == null) {
-                throw new CodePushInvalidUpdateException("Update is invalid - no files with extension .bundle, .js or .jsbundle were found in the update package.");
+                throw new CodePushInvalidUpdateException("Update is invalid - A JS bundle file named \"" + expectedBundleFileName + "\" could not be found within the downloaded contents. Please check that you are releasing your CodePush updates using the exact same JS bundle file name that was shipped with your app's binary.");
             } else {
                 if (FileUtils.fileAtPathExists(newUpdateMetadataPath)) {
                     File metadataFileFromOldUpdate = new File(newUpdateMetadataPath);
diff --git a/ios/CodePush/CodePushPackage.m b/ios/CodePush/CodePushPackage.m
index a0658cc..cba883f 100644
--- a/ios/CodePush/CodePushPackage.m
+++ b/ios/CodePush/CodePushPackage.m
@@ -207,7 +207,9 @@ static NSString *const UnzippedFolderName = @"unzipped";
                                                         if (relativeBundlePath) {
                                                             [mutableUpdatePackage setValue:relativeBundlePath forKey:RelativeBundlePathKey];
                                                         } else {
-                                                            error = [CodePushErrorUtils errorWithMessage:@"Update is invalid - no files with extension .jsbundle or .bundle were found in the update package."];
+                                                            NSString *errorMessage = [NSString stringWithFormat:@"Update is invalid - A JS bundle file named \"%@\" could not be found within the downloaded contents. Please check that you are releasing your CodePush updates using the exact same JS bundle file name that was shipped with your app's binary.", expectedBundleFileName];
+                                                            
+                                                            error = [CodePushErrorUtils errorWithMessage:errorMessage];
                                                             
                                                             failCallback(error);
                                                             return;