diff --git a/Build.bat b/Build.bat
index 6adb3aa..7e5aeb3 100644
--- a/Build.bat
+++ b/Build.bat
@@ -1 +1 @@
-%systemroot%\Microsoft.Net\Framework\v4.0.30319\MSBuild.exe /m build.proj /t:%*
+"c:/Program Files (x86)/Microsoft Visual Studio/2017/Enterprise/MSBuild/15.0/Bin/msbuild.exe" /m build.proj /t:%*
\ No newline at end of file
diff --git a/src/WebApi.OutputCache.V2/CacheOutputAttribute.cs b/src/WebApi.OutputCache.V2/CacheOutputAttribute.cs
index 317a0bc..bbcbf2d 100644
--- a/src/WebApi.OutputCache.V2/CacheOutputAttribute.cs
+++ b/src/WebApi.OutputCache.V2/CacheOutputAttribute.cs
@@ -205,7 +205,16 @@ public override void OnActionExecuting(HttpActionContext actionContext)
             if (val == null) return;
 
             var contenttype = _webApiCache.Get<MediaTypeHeaderValue>(cachekey + Constants.ContentTypeKey) ?? responseMediaType;
-            var contentGenerationTimestamp = DateTimeOffset.Parse(_webApiCache.Get<string>(cachekey + Constants.GenerationTimestampKey));
+            var contentGeneration = _webApiCache.Get<string>(cachekey + Constants.GenerationTimestampKey);
+
+            DateTimeOffset? contentGenerationTimestamp = null;
+            if (contentGeneration != null)
+            {
+                if (DateTimeOffset.TryParse(contentGeneration, out DateTimeOffset parsedContentGenerationTimestamp))
+                {
+                    contentGenerationTimestamp = parsedContentGenerationTimestamp;
+                }
+            };
 
             actionContext.Response = actionContext.Request.CreateResponse();
             actionContext.Response.Content = new ByteArrayContent(val);
diff --git a/test/WebApi.OutputCache.V2.Tests/ClientSideTests.cs b/test/WebApi.OutputCache.V2.Tests/ClientSideTests.cs
index e4b8cc0..132fa5f 100644
--- a/test/WebApi.OutputCache.V2.Tests/ClientSideTests.cs
+++ b/test/WebApi.OutputCache.V2.Tests/ClientSideTests.cs
@@ -123,7 +123,7 @@ public void maxage_mustrevalidate_headers_correct_with_cacheuntil()
         {
             var client = new HttpClient(_server);
             var result = client.GetAsync(_url + "Get_until25012015_1700").Result;
-            var clientTimeSpanSeconds = new SpecificTime(2017, 01, 25, 17, 0, 0).Execute(DateTime.Now).ClientTimeSpan.TotalSeconds;
+            var clientTimeSpanSeconds = new SpecificTime(2019, 01, 25, 17, 0, 0).Execute(DateTime.Now).ClientTimeSpan.TotalSeconds;
             var resultCacheControlSeconds = ((TimeSpan) result.Headers.CacheControl.MaxAge).TotalSeconds;
             Assert.IsTrue(Math.Round(clientTimeSpanSeconds - resultCacheControlSeconds) == 0);
             Assert.IsFalse(result.Headers.CacheControl.MustRevalidate);
diff --git a/test/WebApi.OutputCache.V2.Tests/TestControllers/SampleController.cs b/test/WebApi.OutputCache.V2.Tests/TestControllers/SampleController.cs
index d3b2b11..69c1f20 100644
--- a/test/WebApi.OutputCache.V2.Tests/TestControllers/SampleController.cs
+++ b/test/WebApi.OutputCache.V2.Tests/TestControllers/SampleController.cs
@@ -74,7 +74,7 @@ public string Get_s50_exclude_true(int id)
             return "test" + id;
         }
 
-        [CacheOutputUntil(2017,01,25,17,00)]
+        [CacheOutputUntil(2019,01,25,17,00)]
         public string Get_until25012015_1700()
         {
             return "test";