diff --git a/src/NzbDrone.Core/Parser/Parser.cs b/src/NzbDrone.Core/Parser/Parser.cs
index 8383fd7df..28b77dd08 100644
--- a/src/NzbDrone.Core/Parser/Parser.cs
+++ b/src/NzbDrone.Core/Parser/Parser.cs
@@ -186,7 +186,7 @@ namespace NzbDrone.Core.Parser
                                                                 string.Empty,
                                                                 RegexOptions.IgnoreCase | RegexOptions.Compiled);
 
-        private static readonly Regex ReleaseGroupRegex = new Regex(@"-(?<releasegroup>[a-z0-9]+)(?<!MP3|ALAC|FLAC|WEB)(?:\b|[-._ ])",
+        private static readonly Regex ReleaseGroupRegex = new Regex(@"-(?<releasegroup>[a-z0-9]+(?!.+?(?:MP3|ALAC|FLAC|WEB)))(?<!.*?MP3|ALAC|FLAC|WEB)(?:\b|[-._ ]|$)|[-._ ]\[(?<releasegroup>[a-z0-9]+)\]$",
                                                                 RegexOptions.IgnoreCase | RegexOptions.Compiled);
 
         private static readonly Regex AnimeReleaseGroupRegex = new Regex(@"^(?:\[(?<subgroup>(?!\s).+?(?<!\s))\](?:_|-|\s|\.)?)",