What are the Problems of Prototyping 

In some organisations, theprototyping isn't as successful as anticipated. A common problem with this approach is that people expect much from insufficient effort. As requirements are loosely defined, prototype sometimes gives misleading results about working of software. Prototyping can have execution inefficiencies and this can be questioned as negative aspect of prototyping. Approach of providing early feedback to user may create impression on user and user can carry some negative biasing for completely developed software also.