How do you remove faulty reminders

[WSL]

Something has happened to one of the reminders in outlook. It does not appear
on the calendar, but each time outlook is opened it pops up and cannot be
dismissed.
The error message reads " cannot dismiss or open as finish date is before
start date.
Have tried using detect and repair in help but this has not worked.
It is preventing me synchronising calendar with by blackberry

 

[Roady [MVP]]

Start Outlook with the cleanreminders switch;
Start-> Run; outlook.exe /cleanreminders