diff --git a/src/main/java/com/microsoft/sqlserver/jdbc/IOBuffer.java b/src/main/java/com/microsoft/sqlserver/jdbc/IOBuffer.java
index 067e375b2..7ae6572f3 100644
--- a/src/main/java/com/microsoft/sqlserver/jdbc/IOBuffer.java
+++ b/src/main/java/com/microsoft/sqlserver/jdbc/IOBuffer.java
@@ -4800,6 +4800,7 @@ void writeRPCUUID(String sName, UUID uuidValue, boolean bOut) throws SQLServerEx
 
         if (uuidValue == null) {
             writeByte((byte) 0);
+            writeByte((byte) 0);
 
         } else {
             writeByte((byte) 0x10);  // maximum length = 16
diff --git a/src/main/java/com/microsoft/sqlserver/jdbc/dtv.java b/src/main/java/com/microsoft/sqlserver/jdbc/dtv.java
index e4cc1d4a0..32a1c7626 100644
--- a/src/main/java/com/microsoft/sqlserver/jdbc/dtv.java
+++ b/src/main/java/com/microsoft/sqlserver/jdbc/dtv.java
@@ -295,8 +295,9 @@ final class SendByRPCOp extends DTVExecuteOp {
         void execute(DTV dtv, String strValue) throws SQLServerException {
             if (dtv.getJdbcType() == JDBCType.GUID) {
                 tdsWriter.writeRPCUUID(name, UUID.fromString(strValue), isOutParam);
+            } else {
+                tdsWriter.writeRPCStringUnicode(name, strValue, isOutParam, collation, dtv.isNonPLP);
             }
-            tdsWriter.writeRPCStringUnicode(name, strValue, isOutParam, collation, dtv.isNonPLP);
         }
 
         void execute(DTV dtv, Clob clobValue) throws SQLServerException {