Vusers are not exiting after force stop,scenario is not finishing on time in Load runner

    When ever you run a scenario and that is for set of Hrs and set of  mins, and you may observe that your 

VUsers are not dropping after this time, or they seem to be stalled in gradual exiting state,the reasons
behind this are:
1. Think Time: If your scripts are having exceedingly large think times, and your run time settings allow
a 50 to 150% of recorded think time, these scripts will continue to execute till they have a controlled exit
even after the stipulated schedule.so this may be a cause

2. Pacing : Your Transactions Per Second is what your pacing is. If your scripts have reached an
execution state just before the end of the run, these executions will continue to run till they have a
controlled exit. You might want to adjust the pacing accordingly to achieve exact Transactions Per
Second  you are looking for..so this may be a cause.

3. Load generators : Check the health of your load generators. If your load generators are fighting for
resources, this may cause unforeseen consequences on your schedule..so this may be a cause

      If you are only looking out for the constant 1 hr run and ignore ramp up and ramp down schemes, you
may with out any problem force stop the users. But, in case of tests where you want to look out for the
resource handling, ramp down is a very important step and you may not want to force stop these users.