Hi Carolyn Martus,
Welcome to the Microsoft Q&A forum.
I understand how confusing it can be when you’re setting up a Comcast.net email in the new Outlook and then start seeing unexpected windows appear when doing simple actions like deleting an email.
From your description, it sounds like the account was added, but when you try to delete messages, Outlook shows a pop‑up window instead of deleting the email smoothly. This is commonly seen with third‑party email accounts such as Comcast.net in the new Outlook, because these accounts rely on IMAP server communication for actions like delete, move, or send. When Outlook needs to re‑confirm access with the Comcast mail server, it may prompt with a window rather than completing the action silently.
To help narrow this down accurately, could you please share a bit more detail about that window? For example, does it ask for your email password, mention a server name like imap.comcast.net or smtp.comcast.net, or say something about permissions or authentication? Also, please confirm whether the Comcast account was added as an IMAP account in the new Outlook. This information will help determine whether the pop‑up is an authentication prompt from the Comcast server or a setting that needs adjustment.
Once that detail is clear, the next steps can be tailored specifically to your setup, as the guidance differs depending on whether Outlook is being prompted to re‑authenticate with Comcast or if it’s related to how delete actions are synced over IMAP.
I look forward to your update so the guidance can be matched precisely to what you’re seeing.