Here’s a clear summary you can paste into Apple Support:
Subject: iCloud Mail folders missing in Mac Mail; Inbox shows Read-only
I use iCloud Mail with my custom domain address, ***@***.com. The same mailbox is accessible as ***@icloud.com.
In Outlook for Mac, the account shows my full iCloud folder tree. I can move and delete messages there. In Apple Mail on this Mac, the sidebar shows only Inbox, Drafts, Sent, Spam, Bin and Archive; none of my custom folders appear. The selected Inbox is labelled “Read-only.”
Apple Mail’s Connection Doctor reports that the IMAP connection and login succeeded. The incoming server shown is imap.mail.me.com, with SSL on. The account is enabled and online. “Sync this Mac” is on for iCloud Mail; I toggled it off and back on, but the folders are still missing.
Mail says this iCloud account is shared by other apps on the Mac, so I don’t want to remove the account from Internet Accounts and affect those apps. The Mail sidebar also has two “Recovered Messages” mailboxes under “On My Mac,” which I want to preserve.
Could you help diagnose why Apple Mail isn’t displaying the iCloud folders and why Inbox is read-only, and advise how to refresh Mail safely without affecting the local recovered messages?
[Edited by Moderator]