You may notice that tasks that were past due but you were meaning to complete are now missing. Don't worry they did not disappear, they have likely just expired. Once a task is due, you will have 30 days to complete the task before it expires.
After the task expires you will find it on the Expired Tasks tab in the Tasks applet.
Can I restore an expired task?
You cannot restore an expired task. In this case, you can check the tasks you missed in the expired tab and then complete them and make a note on the contact that you have done the task. Or you can recreate the tasks to give yourself more time to complete the task.
How can I prevent tasks from expiring?
The only way to hold off a task expiring is to Snooze it. You can hit the Snooze icon next to the task to snooze for a specific amount of time. This will keep a past due task from expiring before you're ready.
Manual tasks will expire 30 days after they are due. SmartPlan tasks can vary between 14 and 30 days before a past due task expires depending on the plan.