Many users of the desktop version of Outlook are being confronted with an annoying problem: When you open Outlook, the mail program included in Microsoft 365, it repeatedly asks whether you want to restore previously closed sessions.
Specifically, the dialogue window says Outlook closed while you had items open. Reopen items from last session?
Whether Outlook is closed by a crash, a system update or manually, it doesn't matter: Outlook asks at every restart whether old windows should be restored. Clicking Yes restores draft e-mails and opens all e-mail windows or appointments that were open during the last session.
For many users, the setting responsible for whether you should see those prompts cannot be found in the Outlook options, even though a selection should appear that lets you choose whether Outlook should restore previous contents.
If that's the case for you, the annoying prompt can't be permanently deactivated in the program. The responsible feature was introduced with Outlook for Windows on Beta Channel Version 2006 (Build 13006.20002) a good three years ago. Now, however, it's causing problems because it's activated by default.
The team behind Outlook is still looking for the cause of this annoying behaviour. Until a final solution is found, however, Microsoft is offering a temporary fix that disables recovery and thus bypasses the constant prompting.
Open the Windows registry editor (Regedit) and navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences. There, right-click, hover over New, and create a new DWORD value called ReopenWindowsOption. Give it the value 1. Boom!. After closing Regedit and reopening Outlook, the annoying prompt should no longer appear.