I’m planning to move a few mailboxes away from our current provider, and I’m trying to avoid the classic “everything is still there until suddenly it isn’t” situation. From what I’ve been reading, IMAP migration is mainly about email and folders; contacts, calendars, tasks, rules, etc. generally need separate handling. Microsoft also documents those limitations for IMAP migrations.
For the actual mail, I’m leaning toward making a local backup first. I came across the DRS Softech IMAP backup tool , which can connect to IMAP accounts such as Gmail, Yahoo, Zoho, Outlook.com, and AOL, then export messages into formats including PST, MBOX, EML, MSG, PDF, DOC/DOCX, JSON, and CSV.
What I particularly like is that it can preview the mailbox tree and folder-level counts before starting. There are also date and advanced mail filters, so theoretically I could back up only the required period instead of downloading everything.
Has anyone here taken this backup-first approach before an IMAP migration? Is it worth keeping a separate local copy even when the destination provider offers its own migration facility?