I was getting task scheduler "0" error in windows 7 ultimate. I checked the internet for solutions and non worked. When I looked into the subfolders under windows folder and clicked on those folders there were no tasks listed. There should have been. I upgraded to windows 10 hoping to cure this is as well as some others, rather than reinstalling windows 7. when I look in folders there are now tasks, but I still get errors when I click on task scheduler about missing tasks and it seems to refer to the previous windows 7 tasks. I read that there are two location for the task list one in the registry and one in the system folder. It would seem that only one of the previous windows lists was corrected. I don't know which or how to find the list in the registry and how to compare with list in the system folder and how then to delete the unneeded parts of the list.
You can see from the clip some of the tasks were created by me, but many are system tasks. At any rate I would like to delete all of the erroneous tasks from the list. I just don't know where to find the list.