strange motion trails

hi,
first of all i want to say an “HELLO” to the forum members.today i downloaded krakatoa and rendered some particles.but
i am getting strange motion trails.particle are retainning object shapes for few frames . can anyone give suggestions
to avoid the motion trail problem.

thank you

Hello and welcome!

Does not ring a bell - can you post a screenshot or animation of what you are seeing?
Any additional info would be helpful - what is your particle source, how are the particle generated etc.