diff --git a/lib/common/util.js b/lib/common/util.js
index 819f1261258..f12ca02f8bf 100644
--- a/lib/common/util.js
+++ b/lib/common/util.js
@@ -359,9 +359,17 @@ function makeAuthorizedRequest(config) {
         if (err.code === 401 &&
             ++tokenRefreshAttempts <= MAX_TOKEN_REFRESH_ATTEMPTS) {
           authorize(reqOpts, onAuthorizedRequest);
-        } else {
-          (callback.onAuthorized || callback)(err);
+          return;
         }
+
+        if (err.message === 'SignFinal error') {
+          err.message = [
+            'Your private key is in an unexpected format and cannot be used.',
+            'Please try again with another private key.'
+          ].join(' ');
+        }
+
+        (callback.onAuthorized || callback)(err);
         return;
       }
 
diff --git a/package.json b/package.json
index bde62b4199a..cb8e648779c 100644
--- a/package.json
+++ b/package.json
@@ -46,7 +46,7 @@
   "dependencies": {
     "duplexify": "^3.1.2",
     "extend": "^1.3.0",
-    "google-service-account": "^1.0.0",
+    "google-service-account": "^1.0.3",
     "mime": "^1.2.11",
     "node-uuid": "^1.4.1",
     "protobufjs": "^3.4.0",
diff --git a/test/common/util.js b/test/common/util.js
index f9fd0a234bb..3cb82b85758 100644
--- a/test/common/util.js
+++ b/test/common/util.js
@@ -20,6 +20,7 @@
 
 var assert = require('assert');
 var duplexify = require('duplexify');
+var gsa = require('google-service-account');
 var request = require('request');
 
 var util = require('sandboxed-module')
@@ -31,20 +32,17 @@ var util = require('sandboxed-module')
   });
 
 var gsa_Override;
-
 function fakeGsa() {
   var args = [].slice.apply(arguments);
-  var results = (gsa_Override || util.noop).apply(null, args);
+  var results = (gsa_Override || gsa).apply(null, args);
   gsa_Override = null;
   return results || { getCredentials: util.noop };
 }
 
-var request_Cached = request;
 var request_Override;
-
 function fakeRequest() {
   var args = [].slice.apply(arguments);
-  var results = (request_Override || request_Cached).apply(null, args);
+  var results = (request_Override || request).apply(null, args);
   request_Override = null;
   return results;
 }
@@ -322,6 +320,24 @@ describe('common/util', function() {
         });
       });
 
+      it('should handle malformed key response', function(done) {
+        var makeRequest = util.makeAuthorizedRequest({
+          credentials: {
+            client_email: 'invalid@email',
+            private_key: 'invalid-key'
+          }
+        });
+
+        makeRequest({}, function (err) {
+          var errorMessage = [
+            'Your private key is in an unexpected format and cannot be used.',
+            'Please try again with another private key.'
+          ].join(' ');
+          assert.equal(err.message, errorMessage);
+          done();
+        });
+      });
+
       it('should try to reconnect if token invalid', function(done) {
         var attempts = 0;
         var expectedAttempts = 2;