I started to use filters on my incoming email in ms outlook (office 2019 pro) to split it into different (sub)folders. But now the outlook envelope icon no longer shows in the taskbar when a new email arrives. The incoming email is split based on the "to" address. It 's an email account with several aliases, which are delivered to the same inbox on the server. Is there a way to keep the envelope icon in the taskbar and still split the new email into different (sub)folders?

Create a smart folder

Thanks for the input, but I think smart folders are only available in the MAC version.

If you mean "Search Folders", they are available in Classic Outlook for Windows.

Not sure if you will look at this, but might help others.
Have a look in the 'Show hidden icons' menu, small upward arrow, in the Notification Area.
In my experience, the incoming mail notification envelope goes there and simply dragging it out into the Notification Area, will send the envelope there in the future when mail arrives so you can view it more easily.
When you have viewed the message(s), the envelope will disappear.

Do I understand correctly, that you are using Rules to move incoming emails to folders? If so, then you will not get a New Mail notification for those emails.

https://www.reddit.com/r/Office365/c...ifications_in/

You may be able to get the process you want by adding a "display a Desktop Alert" action to your Rules.