diff --git a/QuickFIXn/Store/FileStore.cs b/QuickFIXn/Store/FileStore.cs
index 770f11659..3820bf092 100755
--- a/QuickFIXn/Store/FileStore.cs
+++ b/QuickFIXn/Store/FileStore.cs
@@ -269,10 +269,11 @@ public void IncrNextTargetMsgSeqNum()
     private void SetSeqNum()
     {
         _seqNumsFile.Seek(0, System.IO.SeekOrigin.Begin);
-        System.IO.StreamWriter writer = new System.IO.StreamWriter(_seqNumsFile);
+        System.IO.StreamWriter writer = new System.IO.StreamWriter(_seqNumsFile, leaveOpen: true);
 
         writer.Write(NextSenderMsgSeqNum.ToString("D20") + " : " + NextTargetMsgSeqNum.ToString("D20") + "  ");
         writer.Flush();
+        writer.Dispose();
     }
 
     public DateTime? CreationTime => _cache.CreationTime;