Backup Exec has trouble handling schedules when Daylight Savings starts & stops. This has been a problem since at least Backup Exec 7, and continues with all versions though Backup Exec 12.
For example, in the United States, Daylight Savings starts the 2nd Sunday in March (clocks move forward 1 hour), and ends the 1st Sunday in November (clocks move back 1 hour). Both changes happen at 2:00am.
In some cases the Backup Exec server will not recognize the time change, even though the system clock on the hardware has changed. Backup jobs and database maintenance will run 1 hour off of when they should have run. The solution in this case is to restart the Backup Exec services or reboot the server.
In other cases, jobs are incorrectly rescheduled the day before or after the time change. This results in the symptom of backup jobs that are scheduled but have not yet run at 2:00am being report as "missed". This is a one-time problem- jobs will run again normally the next day. This most often happens on daily jobs.
Another commonly reported problem is a job reporting as "missed", and all future runs of that job also immediately halt and report "missed". This most often happens on jobs scheduled less than daily (i.e. weekly or monthly). The easiest solution is to edit the start time of the job with a different time. Even adding 1 second to the start time is sufficient. Future runs of the job should be normal.
Rare reports on the support forums show schedule corruptions or jobs being moved by a week. These problems can only be fixed by deleted & recreating the affected jobs.
A best practice recommendation is to avoid having jobs start at 1:00am and 2:00am, and watch backup jobs closely during both the start and end of Daylight Savings.
Symantec claims to have fixed the Daylight Savings problems in v11 with HotFix 16, however many people still report problems.Symantec does acknowledge some of these problems with Daylight Savings:
Document ID: 267203
Due to time changes related to daylight savings time Backup Exec for Windows Servers jobs will run one hour before or one hour after the previously defined schedule.
Document ID: 287693
Backup Exec 11d for Windows Servers: Daylight Saving Time transition causing missed backup jobs.
Document ID: 301124
Missed backup jobs during Daylight Savings Time (versions 12, 11d 7170, 11d 6235, 10d, 10.0)