When I open the app, I see a list of completed tasks, between 105 & 81 days old. How do I stop them from appearing?
Are these tasks part of a parent task, do they appear crossed out and grey? Did you do any custom search query recently? Any view should be able to change by selecting a new view from the left hand menu.
Please head into your Android Settings area --> Applications --> and find Todoist, clear Data. This should allow you to get back to the main area no matter the issue.