diff --git a/src/Orchard.Tests/Localization/DefaultDateFormatterTests.cs b/src/Orchard.Tests/Localization/DefaultDateFormatterTests.cs
index 761a22813..52f99462a 100644
--- a/src/Orchard.Tests/Localization/DefaultDateFormatterTests.cs
+++ b/src/Orchard.Tests/Localization/DefaultDateFormatterTests.cs
@@ -52,6 +52,10 @@ namespace Orchard.Framework.Tests.Localization {
             IDateFormatter target = new DefaultDateFormatter();
             var cultures = CultureInfo.GetCultures(CultureTypes.AllCultures);
             foreach (CultureInfo cultureInfo in cultures) {
+                // Due to a bug in .NET 4.5 in combination with updated Upper Sorbian culture in Windows 8.
+                if (System.Environment.OSVersion.Version.ToString().CompareTo("6.2.0.0") >= 0 && cultureInfo.Name.StartsWith("hsb")) {
+                    continue;
+                }
                 DateTime dateTime = new DateTime(2014, 12, 31, 10, 20, 40, 567);
                 cultureInfo.DateTimeFormat.Calendar = new GregorianCalendar();
                 var dateString = dateTime.ToString("G", cultureInfo);
diff --git a/src/Orchard/Localization/Services/DefaultDateFormatter.cs b/src/Orchard/Localization/Services/DefaultDateFormatter.cs
index e1771fdea..98da1a2b4 100644
--- a/src/Orchard/Localization/Services/DefaultDateFormatter.cs
+++ b/src/Orchard/Localization/Services/DefaultDateFormatter.cs
@@ -97,8 +97,8 @@ namespace Orchard.Framework.Localization.Services {
                 {"ddd", String.Format("(?<day>{0})", String.Join("|", culture.DateTimeFormat.AbbreviatedDayNames))},
                 {"dd", "(?<day>[0-9]{2})"},
                 {"d", "(?<day>[0-9]{1,2})"},
-                {"MMMM", String.Format("(?<month>{0})", String.Join("|", culture.DateTimeFormat.MonthNames))},
-                {"MMM", String.Format("(?<month>{0})", String.Join("|", culture.DateTimeFormat.AbbreviatedMonthNames))},
+                {"MMMM", String.Format("(?<month>{0})", String.Join("|", culture.DateTimeFormat.MonthNames.Where(x => !String.IsNullOrEmpty(x))))},
+                {"MMM", String.Format("(?<month>{0})", String.Join("|", culture.DateTimeFormat.AbbreviatedMonthNames.Where(x => !String.IsNullOrEmpty(x))))},
                 {"MM", "(?<month>[0-9]{2})"},
                 {"M", "(?<month>[0-9]{1,2})"},
                 {"yyyyy", "(?<year>[0-9]{5})"},