diff --git a/src/NzbDrone.Core.Test/OrganizerTests/FileNameBuilderTests/ReservedDeviceNameFixture.cs b/src/NzbDrone.Core.Test/OrganizerTests/FileNameBuilderTests/ReservedDeviceNameFixture.cs
new file mode 100644
index 000000000..383fbf64f
--- /dev/null
+++ b/src/NzbDrone.Core.Test/OrganizerTests/FileNameBuilderTests/ReservedDeviceNameFixture.cs
@@ -0,0 +1,68 @@
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using FizzWare.NBuilder;
+using FluentAssertions;
+using Moq;
+using NUnit.Framework;
+using NzbDrone.Core.MediaFiles;
+using NzbDrone.Core.MediaFiles.MediaInfo;
+using NzbDrone.Core.Movies;
+using NzbDrone.Core.Organizer;
+using NzbDrone.Core.Qualities;
+using NzbDrone.Core.Test.Framework;
+using NzbDrone.Test.Common;
+
+namespace NzbDrone.Core.Test.OrganizerTests.FileNameBuilderTests
+{
+    [TestFixture]
+
+    public class ReservedDeviceNameFixture : CoreTest<FileNameBuilder>
+    {
+        private Movie _movie;
+        private MovieFile _movieFile;
+        private NamingConfig _namingConfig;
+
+        [SetUp]
+        public void Setup()
+        {
+            _movie = Builder<Movie>
+                    .CreateNew()
+                    .Build();
+
+            _namingConfig = NamingConfig.Default;
+            _namingConfig.RenameMovies = true;
+
+            Mocker.GetMock<INamingConfigService>()
+                  .Setup(c => c.GetConfig()).Returns(_namingConfig);
+
+            _movieFile = new MovieFile { Quality = new QualityModel(Quality.HDTV720p), ReleaseGroup = "SonarrTest" };
+
+            Mocker.GetMock<IQualityDefinitionService>()
+                .Setup(v => v.Get(Moq.It.IsAny<Quality>()))
+                .Returns<Quality>(v => Quality.DefaultQualityDefinitions.First(c => c.Quality == v));
+        }
+
+        [Test]
+        public void should_replace_reserved_device_name_in_movies_folder()
+        {
+            _movie.Title = "Con Man";
+            _movie.Year = 2021;
+            _namingConfig.MovieFolderFormat = "{Movie.Title} ({Release Year})";
+
+            Subject.GetMovieFolder(_movie).Should().Be("Con_Man (2021)");
+        }
+
+        [Test]
+        public void should_replace_reserved_device_name_in_file_name()
+        {
+            _movie.Title = "Con Man";
+            _movie.Year = 2021;
+            _namingConfig.StandardMovieFormat = "{Movie.Title} ({Release Year})";
+
+            Subject.BuildFileName(_movie, _movieFile).Should().Be("Con_Man (2021)");
+        }
+    }
+}
diff --git a/src/NzbDrone.Core/Organizer/FileNameBuilder.cs b/src/NzbDrone.Core/Organizer/FileNameBuilder.cs
index 1990a1a4f..3e6d91a1a 100644
--- a/src/NzbDrone.Core/Organizer/FileNameBuilder.cs
+++ b/src/NzbDrone.Core/Organizer/FileNameBuilder.cs
@@ -67,6 +67,8 @@ public class FileNameBuilder : IBuildFileNames
 
         private static readonly Regex TitlePrefixRegex = new Regex(@"^(The|An|A) (.*?)((?: *\([^)]+\))*)$", RegexOptions.Compiled | RegexOptions.IgnoreCase);
 
+        private static readonly Regex ReservedDeviceNamesRegex = new Regex(@"^(?:aux|com1|com2|com3|com4|com5|com6|com7|com8|com9|con|lpt1|lpt2|lpt3|lpt4|lpt5|lpt6|lpt7|lpt8|lpt9|nul|prn)\.", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+
         public FileNameBuilder(INamingConfigService namingConfigService,
                                IQualityDefinitionService qualityDefinitionService,
                                IUpdateMediaInfo mediaInfoUpdater,
@@ -119,6 +121,7 @@ public string BuildFileName(Movie movie, MovieFile movieFile, NamingConfig namin
 
                 component = FileNameCleanupRegex.Replace(component, match => match.Captures[0].Value[0].ToString());
                 component = TrimSeparatorsRegex.Replace(component, string.Empty);
+                component = ReplaceReservedDeviceNames(component);
 
                 if (component.IsNotNullOrWhiteSpace())
                 {
@@ -180,6 +183,7 @@ public string GetMovieFolder(Movie movie, NamingConfig namingConfig = null)
 
                 var component = ReplaceTokens(splitPattern, tokenHandlers, namingConfig);
                 component = CleanFolderName(component);
+                component = ReplaceReservedDeviceNames(component);
 
                 if (component.IsNotNullOrWhiteSpace())
                 {
@@ -566,6 +570,12 @@ private string GetOriginalFileName(MovieFile movieFile)
 
             return Path.GetFileNameWithoutExtension(movieFile.RelativePath);
         }
+
+        private string ReplaceReservedDeviceNames(string input)
+        {
+            // Replace reserved windows device names with an alternative
+            return ReservedDeviceNamesRegex.Replace(input, match => match.Value.Replace(".", "_"));
+        }
     }
 
     internal sealed class TokenMatch