Microsoft To Do Tasks Disappeared

Viterbi I just noticed this problem today, and I determined that my old tasks were being archived to my "Online Archive" in Exchange Online. I was able to move my old tasks back to my mailbox "Tasks" folder/sub-folders and they reappeared in To Do, but I fear this is going to happen again on the next archive cycle. I keep a research list with things I need to get to eventually, and most of my lost content was in that list, but I had several regular Tasks that went missing because I was working on another long term project and didn't have time for those Tasks. So... check with your organization's administrator, and most likely the culprit is online archiving. It looks like Microsoft To Do stops showing tasks that end up in the online archive. One of two things needs to happen to prevent this: (1) have your administrator configure a retention policy so Tasks and sub-folders do not get archived, or (2) Microsoft needs to update To Do so it shows tasks in the Online Archive.