diff --git a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
index bc7cd362a8..a73e24a098 100644
--- a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
+++ b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
@@ -4,8 +4,10 @@
 
 using System;
 using System.Diagnostics;
+using System.Linq;
 using System.Runtime.InteropServices;
 using System.Security;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Data.Common;
@@ -359,7 +361,7 @@ public bool TryReadByteArray(Span<byte> buff, int len)
         public bool TryReadByteArray(Span<byte> buff, int len, out int totalRead)
         {
             totalRead = 0;
-
+            int inBytesPacketStart = _inBytesPacket;
 #if DEBUG
             if (_snapshot != null && _snapshot.DoPend())
             {
@@ -396,9 +398,27 @@ public bool TryReadByteArray(Span<byte> buff, int len, out int totalRead)
                 Debug.Assert(bytesToRead > 0, "0 byte read in TryReadByteArray");
                 if (!buff.IsEmpty)
                 {
-                    ReadOnlySpan<byte> copyFrom = new ReadOnlySpan<byte>(_inBuff, _inBytesUsed, bytesToRead);
-                    Span<byte> copyTo = buff.Slice(totalRead, bytesToRead);
-                    copyFrom.CopyTo(copyTo);
+                    ReadOnlySpan<byte> copyFrom = ReadOnlySpan<byte>.Empty;
+                    try
+                    {
+                        copyFrom = new ReadOnlySpan<byte>(_inBuff, _inBytesUsed, bytesToRead);
+                        Span<byte> copyTo = buff.Slice(totalRead, bytesToRead);
+                        copyFrom.CopyTo(copyTo);
+                    }
+                    catch (Exception ex)
+                    {
+                        string debugmsg = "\n" +
+                            $"inBytesPacketStart = {inBytesPacketStart}\n" +
+                            $"bytesToRead = Math.Min({len}, Math.Min({_inBytesPacket}, {_inBytesRead} - {_inBytesUsed}));\n" +
+                            $"_inBuff.Length = {_inBuff.Length}\n" +
+                            $"buff.Length = {buff.Length}\n" +
+                            $"copyFrom = new ReadOnlySpan<byte>({_inBuff.Length}, {_inBytesUsed}, {bytesToRead})\n" +
+                            $"copyTo = buff.Slice({totalRead}, {bytesToRead});\n" +
+                            $"lengths= {inBytesPacketStart}\n"+
+                            ex.Message;
+                        Console.WriteLine(debugmsg);
+                        throw new Exception(debugmsg);
+                    }
                 }
 
                 totalRead += bytesToRead;
@@ -465,6 +485,11 @@ internal bool TryReadChar(out char value)
             Span<byte> buffer = stackalloc byte[2];
             if (((_inBytesUsed + 2) > _inBytesRead) || (_inBytesPacket < 2))
             {
+                if (_inBytesPacket < 0)
+                {
+                    throw new Exception($"TryReadChar(0) _inBytesPacket  {_inBytesPacket}\n" +
+                        $"  if ((({_inBytesUsed} + 2) > {_inBytesRead}) || ({_inBytesPacket} < 2))");
+                }
                 // If the char isn't fully in the buffer, or if it isn't fully in the packet,
                 // then use ReadByteArray since the logic is there to take care of that.
                 if (!TryReadByteArray(buffer, 2))
diff --git a/src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs b/src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
index d8171c63b6..5f8ed19ca0 100644
--- a/src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
+++ b/src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
@@ -10,6 +10,7 @@
 using System.Runtime.ConstrainedExecution;
 using System.Runtime.InteropServices;
 using System.Security;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Data.Common;
@@ -449,7 +450,6 @@ public bool TryReadByteArray(Span<byte> buff, int len, out int totalRead)
         {
             TdsParser.ReliabilitySection.Assert("unreliable call to ReadByteArray");  // you need to setup for a thread abort somewhere before you call this method
             totalRead = 0;
-
 #if DEBUG
             if (_snapshot != null && _snapshot.DoPend())
             {
diff --git a/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs b/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
index e32b84d672..993bf36806 100644
--- a/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
+++ b/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
@@ -439,14 +439,16 @@ internal bool TryStartNewRow(bool isNullCompressed, int nullBitmapColumnsCount =
         internal bool TryReadChars(char[] chars, int charsOffset, int charsCount, out int charsCopied)
         {
             charsCopied = 0;
+            int count = 0;
             while (charsCopied < charsCount)
             {
                 // check if the current buffer contains some bytes we need to copy and copy them
                 //  in a block
                 int bytesToRead = Math.Min(
                     (charsCount - charsCopied) * 2,
-                    unchecked((_inBytesRead - _inBytesUsed) & (int)0xFFFFFFFE) // it the result is odd take off the 0 to make it even
+                    unchecked((_inBytesRead - _inBytesUsed) & (int)0xFFFFFFFE) // if the result is odd take off the 0 to make it even
                 );
+                
                 if (bytesToRead > 0)
                 {
                     Buffer.BlockCopy(
@@ -456,6 +458,13 @@ internal bool TryReadChars(char[] chars, int charsOffset, int charsCount, out in
                         (charsOffset + charsCopied) * 2, // offset in bytes,
                         bytesToRead
                     );
+
+                    if ((_inBytesPacket - bytesToRead) < 0)
+                    {
+                        throw new Exception($"TryReadChars() {count} _inBytesPacket  {_inBytesPacket}\n" +
+                            $"  bytesToRead = Math.Min(({charsCount} - {charsCopied}) * 2, unchecked(({_inBytesRead} - {_inBytesUsed}) & (int)0xFFFFFFFE)");
+                    }
+
                     charsCopied = bytesToRead / 2;
                     _inBytesUsed += bytesToRead;
                     _inBytesPacket -= bytesToRead;
@@ -477,6 +486,7 @@ internal bool TryReadChars(char[] chars, int charsOffset, int charsCount, out in
                         return false;
                     }
                 }
+                count += 1;
             }
             return true;
         }