diff --git a/SharpCompress/IO/CountingWritableSubStream.cs b/SharpCompress/IO/CountingWritableSubStream.cs
index 3ba15008..ef493445 100644
--- a/SharpCompress/IO/CountingWritableSubStream.cs
+++ b/SharpCompress/IO/CountingWritableSubStream.cs
@@ -35,28 +35,28 @@ namespace SharpCompress.IO
 
         public override long Length
         {
-            get { throw new NotImplementedException(); }
+            get { throw new NotSupportedException(); }
         }
 
         public override long Position
         {
-            get { throw new NotImplementedException(); }
-            set { throw new NotImplementedException(); }
+            get { throw new NotSupportedException(); }
+            set { throw new NotSupportedException(); }
         }
 
         public override int Read(byte[] buffer, int offset, int count)
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override long Seek(long offset, SeekOrigin origin)
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override void SetLength(long value)
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override void Write(byte[] buffer, int offset, int count)
diff --git a/SharpCompress/IO/MarkingBinaryReader.cs b/SharpCompress/IO/MarkingBinaryReader.cs
index 4864309f..a9a5d1be 100644
--- a/SharpCompress/IO/MarkingBinaryReader.cs
+++ b/SharpCompress/IO/MarkingBinaryReader.cs
@@ -21,17 +21,17 @@ namespace SharpCompress.IO
 
         public override int Read()
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override int Read(byte[] buffer, int index, int count)
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override int Read(char[] buffer, int index, int count)
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override bool ReadBoolean()
@@ -57,12 +57,12 @@ namespace SharpCompress.IO
 
         public override char ReadChar()
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override char[] ReadChars(int count)
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
 #if !PORTABLE
@@ -115,7 +115,7 @@ namespace SharpCompress.IO
 
         public override string ReadString()
         {
-            throw new NotImplementedException();
+            throw new NotSupportedException();
         }
 
         public override ushort ReadUInt16()
diff --git a/SharpCompress/IO/ReadOnlySubStream.cs b/SharpCompress/IO/ReadOnlySubStream.cs
index 5761fdb7..21b7dd76 100644
--- a/SharpCompress/IO/ReadOnlySubStream.cs
+++ b/SharpCompress/IO/ReadOnlySubStream.cs
@@ -48,18 +48,18 @@ namespace SharpCompress.IO
 
         public override void Flush()
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
 
         public override long Length
         {
-            get { throw new System.NotImplementedException(); }
+            get { throw new System.NotSupportedException(); }
         }
 
         public override long Position
         {
-            get { throw new System.NotImplementedException(); }
-            set { throw new System.NotImplementedException(); }
+            get { throw new System.NotSupportedException(); }
+            set { throw new System.NotSupportedException(); }
         }
 
         public override int Read(byte[] buffer, int offset, int count)
@@ -78,17 +78,17 @@ namespace SharpCompress.IO
 
         public override long Seek(long offset, SeekOrigin origin)
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
 
         public override void SetLength(long value)
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
 
         public override void Write(byte[] buffer, int offset, int count)
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
     }
 }
\ No newline at end of file
diff --git a/SharpCompress/IO/RewindableStream.cs b/SharpCompress/IO/RewindableStream.cs
index 6e8fe060..7946eec6 100644
--- a/SharpCompress/IO/RewindableStream.cs
+++ b/SharpCompress/IO/RewindableStream.cs
@@ -84,12 +84,12 @@ namespace SharpCompress.IO
 
         public override void Flush()
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
 
         public override long Length
         {
-            get { throw new System.NotImplementedException(); }
+            get { throw new System.NotSupportedException(); }
         }
 
         public override long Position
@@ -147,17 +147,17 @@ namespace SharpCompress.IO
 
         public override long Seek(long offset, SeekOrigin origin)
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
 
         public override void SetLength(long value)
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
 
         public override void Write(byte[] buffer, int offset, int count)
         {
-            throw new System.NotImplementedException();
+            throw new System.NotSupportedException();
         }
     }
 }
\ No newline at end of file