I have two IMAP folders that I can't delete: spam and Archive. The option, accessible via right-click, is greyed out in Outlook. I am not subscribed to them. I don't see them on the server in Roundcube's list of folders on the mail tab, but they do appear in the Settings -> Folders list. I tried to delete them from here, but after reloading the page they reappear. My Outlook has only the standard Add-ins, CompanionLink, and GpgOL.