diff --git a/src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack_cpp.cs b/src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack_cpp.cs
index 4126bf34..5645edec 100644
--- a/src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack_cpp.cs
+++ b/src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack_cpp.cs
@@ -283,6 +283,7 @@ void MakeDecodeTables(byte[] LengthTable, int offset, DecodeTable Dec,uint Size)
   // so we cannot use the original DecodePos.
   uint[] CopyDecodePos = new uint[Dec.DecodePos.Length];
   //memcpy(CopyDecodePos,Dec->DecodePos,sizeof(CopyDecodePos));
+  Array.Copy(Dec.DecodePos, 0, CopyDecodePos, 0, CopyDecodePos.Length);
 
   // For every bit length in the bit length table and so for every item
   // of alphabet.