diff --git a/BizHawk.Emulation.DiscSystem/CDFS/ISODirectoryNode.cs b/BizHawk.Emulation.DiscSystem/CDFS/ISODirectoryNode.cs
index e2bbfb000c..07e8e71731 100644
--- a/BizHawk.Emulation.DiscSystem/CDFS/ISODirectoryNode.cs
+++ b/BizHawk.Emulation.DiscSystem/CDFS/ISODirectoryNode.cs
@@ -109,10 +109,9 @@ namespace BizHawk.Emulation.DiscSystem
 			{
 				// Parse this node
 				if (child.Key != ISONodeRecord.CURRENT_DIRECTORY &&
-					child.Key != ISONodeRecord.PARENT_DIRECTORY &&
-					child.Value is ISODirectoryNode)
+					child.Key != ISONodeRecord.PARENT_DIRECTORY)
 				{
-					((ISODirectoryNode)child.Value).Parse(s, visited);
+					(child.Value as ISODirectoryNode)?.Parse(s, visited);
 				}
 			}
 
@@ -146,10 +145,9 @@ namespace BizHawk.Emulation.DiscSystem
 				ISONode n = this.Children[s];
 				Console.WriteLine(tabs + s);
 				if (s != ISONodeRecord.CURRENT_DIRECTORY &&
-					s != ISONodeRecord.PARENT_DIRECTORY &&
-					n is ISODirectoryNode)
+					s != ISONodeRecord.PARENT_DIRECTORY)
 				{
-					((ISODirectoryNode)n).Print(depth + 1);
+					(n as ISODirectoryNode)?.Print(depth + 1);
 				}
 			}
 		}
diff --git a/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/Blob_ECM.cs b/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/Blob_ECM.cs
index 0562ed367a..a719c71411 100644
--- a/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/Blob_ECM.cs
+++ b/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/Blob_ECM.cs
@@ -40,8 +40,7 @@ namespace BizHawk.Emulation.DiscSystem
 			
 			public void Dispose()
 			{
-				if(stream != null)
-					stream.Dispose();
+				stream?.Dispose();
 				stream = null;
 			}
 
diff --git a/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/RiffMaster.cs b/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/RiffMaster.cs
index 8bb8753b7e..2453b54907 100644
--- a/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/RiffMaster.cs
+++ b/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/RiffMaster.cs
@@ -36,7 +36,7 @@ namespace BizHawk.Emulation.DiscSystem
 
 		public void Dispose()
 		{
-			if (BaseStream != null) BaseStream.Dispose();
+			BaseStream?.Dispose();
 			BaseStream = null;
 		}