Outlook: prepare Conversation Clean Up

For your own desktop Outlook for Microsoft 365 with these controls; other clients are outside scope.

Clean Up removes earlier messages whose content is completely contained in replies. It is not a junk assessment or an instruction to delete the entire thread.

Before proceeding, inspect File → Options → Mail, the cleanup settings. Choose exemptions for unread, categorized, flagged or digitally signed messages, and originals altered in quoted replies. Categories and flags belong to individual messages; do not assume exemptions are enabled. Confirm destination: normally the account’s Deleted Items, but configurable. Detailed options.

For one selected conversation: Home → Clean Up → Clean Up Conversation on the classic ribbon; on the simplified ribbon, use Home’s Delete arrow. Confirm if prompted. Folder commands cover every conversation there; the subfolder variant extends further. Selection route.

Leave the recommendation pending if scope, preservation requirements or controls are unresolved. No attachment, recovery or storage-saving result is established.

Evidence: Both Microsoft pages read through 2026-10-05T21:31:17Z; no update dates displayed. Sixteen synthetic manual reader decisions were checked. No mailbox, message, setting, cleanup or recovery was accessed or performed. A distinct same-controller checker reread both sources and checked the sixteen author decisions plus six additional boundaries; no independent review is claimed. Recheck before use, after changed controls or requirements, and by 2026-11-05T21:31:17Z. Follow the email standard [current article]. Report the unclear branch without private mail or identifiers.