Multiple Calendar Use

here are 10 items to check 

item #1 as stated by Alexandre check your TIMES turn them on by selecting Edit, User Preference, then select the Dates tab at the bottom under Time select 12 hour and show minutes

item #2 Also check you durations in the users preferences click on the Time units and under Durations Format make sure that the decimal is 2 places. If you have ANY original durations or remaining durations that that are not whole numbers change these to whole numbers.

item #3 check ALL constraint dates for the start constraints make sure that the start TIME is 8:00 am or the earliest time in anyy of your calendars being used.

item #4 check ALL constraint dates for the finish constraints make sure that the finish TIME is 5:00 pm or the end of the latest time in anyy of your calendars being used.

item #6 make sure that your Project START TIME is 8:00 am or the earliest time in anyy of your calendars being used.

item #7 make sure that your project must finish by date TIME is correct the finish TIME should be 5:00 pm or the end of the latest time in anyy of your calendars being used.

item #8 for any activites that are in progress make sure that the actual start date TIMES are correct that the ACTUAL START TIME is 8:00 am or the earliest time in anyy of your calendars being used.

item #9 make sure that the data date TIME is correct make sure that the start TIME is 8:00 am or the earliest time in anyy of your calendars being used.

item #10 if all of these are correct then select tools then schedule then options then at the bottom where it says calendar fir scheduling Relationship Lag select Successor Activity calendar. 

theses are the only things that can affect this.