Biztalk : Illegal attempt to update the value of part ‘part’ in XLANG/s message ‘testMsg’ after the message construction was complete.

When you are receiving a message and will go to update it in the expression shape, you will receive this type of error. To resolve this you need to construct the new message of the same type and needs to update the value of it in the construct shape using Message Assignment shape.

Regards,
Vijay Modi