Not too long ago we managed to come across something that seems to work quite well. In fact, it worked for us, so we are now hoping the same procedures will also do wonders for you as well.
Delete old email IDs from auto-complete list in Outlook
The auto-complete feature in the Office 365 Outlook app is important as you get to see the old email addresses that you have used in the drop-down – but it can be a bit annoying at times. 1] Remove individual addresses OK, so now we’re going to talk about how to delete individual email addresses from autocomplete. Please launch the Outlook app from the Start menu, then click on New Mail from within the app, then type the first letter of the address in the To section. You should now see a list, right? Hover the mouse cursor over any of the options from the list, and click on the X at the right to remove the address. 2] Turn off the Auto-Complete List
If you’re tired of having to deal with the auto-complete feature, then worry not because the option is there to turn it off completely. In order to get this done, click on File, Options, and then Mail. Under the section that says Send messages, clear the Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines check box. 3] Delete all entries from the Auto-Complete List
Clearing everything from the auto-complete list is possible in the Outlook app, but not so in the Mail app at the time of writing. Delete all entries by going to File > Options > Mail. Now, under Send messages, choose Empty Auto-Complete List. If you’re looking to do this in the Mail app, then we’re sorry to say that Microsoft has yet to provide an official way to get it done. Nevertheless, you should subscribe to us, and no doubt whenever this is possible, you’ll get an update.