diff --git a/src/BizHawk.Client.Common/SharpCompressArchiveFile.cs b/src/BizHawk.Client.Common/SharpCompressArchiveFile.cs
index d58dfc279c..8a02fa6b6f 100644
--- a/src/BizHawk.Client.Common/SharpCompressArchiveFile.cs
+++ b/src/BizHawk.Client.Common/SharpCompressArchiveFile.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -12,41 +14,34 @@ namespace BizHawk.Client.Common
 	/// <see cref="SharpCompressDearchivalMethod"/>
 	public class SharpCompressArchiveFile : IHawkArchiveFile
 	{
-		private IArchive _archive;
+		private IArchive? _archive;
 
-		private IEnumerable<IArchiveEntry> EnumerateArchiveFiles()
+		private IEnumerable<IArchiveEntry> EnumerateArchiveFiles()
 		{
-			if (_archive == null)
-				throw new ObjectDisposedException(nameof(SharpCompressArchiveFile));
-			return _archive.Entries.Where(e => !e.IsDirectory);
+			if (_archive == null) throw new ObjectDisposedException(nameof(SharpCompressArchiveFile));
+			return _archive.Entries.Where(e => !e.IsDirectory);
 		}
 
-		public SharpCompressArchiveFile(string path)
-		{
-			var readerOptions = new SharpCompress.Readers.ReaderOptions();
-			_archive = ArchiveFactory.Open(path, readerOptions);
-		}
+		public SharpCompressArchiveFile(string path) => _archive = ArchiveFactory.Open(path, new());
 
 		public void Dispose()
 		{
-			_archive.Dispose();
+			_archive?.Dispose();
 			_archive = null;
 		}
 
 		public void ExtractFile(int index, Stream stream)
-		{
-			var reader = _archive.ExtractAllEntries();
-			for(int i=0;i<=index;i++)
-				reader.MoveToNextEntry();
-
+		{
+			var reader = _archive!.ExtractAllEntries();
+			for (var i = 0; i <= index; i++) reader.MoveToNextEntry();
 			using var entryStream = reader.OpenEntryStream();
 			entryStream.CopyTo(stream);
 		}
 
-		public List<HawkArchiveFileItem> Scan()
+		public List<HawkArchiveFileItem> Scan()
 		{
 			var files = EnumerateArchiveFiles();
-			return files.Select((e, i) => new HawkArchiveFileItem(e.Key.Replace('\\', '/'), e.Size, i, i)).ToList();
+			return files.Select((e, i) => new HawkArchiveFileItem(e.Key.Replace('\\', '/'), e.Size, i, i)).ToList();
 		}
 	}
 }
diff --git a/src/BizHawk.Client.Common/SharpCompressDearchivalMethod.cs b/src/BizHawk.Client.Common/SharpCompressDearchivalMethod.cs
index 9b716ae838..a472ea6cb1 100644
--- a/src/BizHawk.Client.Common/SharpCompressDearchivalMethod.cs
+++ b/src/BizHawk.Client.Common/SharpCompressDearchivalMethod.cs
@@ -1,7 +1,9 @@
-using System.IO;
-using System.Linq;
+#nullable enable
+
 using System.Collections.Generic;
+
 using BizHawk.Common;
+
 using SharpCompress.Archives;
 
 namespace BizHawk.Client.Common
@@ -27,13 +29,10 @@ namespace BizHawk.Client.Common
 			return true; // no exception? good enough
 		}
 
-		public SharpCompressArchiveFile Construct(string path) => new SharpCompressArchiveFile(path);
+		public SharpCompressArchiveFile Construct(string path) => new(path);
 
-		public static readonly SharpCompressDearchivalMethod Instance = new SharpCompressDearchivalMethod();
-
-		//don't try any .tar.* formats, they don't work
-		static readonly IReadOnlyCollection<string> archiveExts = new[] { ".zip", ".7z", ".rar", ".gz" };
+		public static readonly SharpCompressDearchivalMethod Instance = new();
 
-		public IReadOnlyCollection<string> AllowedArchiveExtensions { get { return archiveExts; } }
+		public IReadOnlyCollection<string> AllowedArchiveExtensions { get; } = new[] { ".zip", ".7z", ".rar", ".gz" }; // don't try any .tar.* formats, they don't work
 	}
 }
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