<p data-start="0" data-end="431">To delete duplicates in your Outlook mailbox, you can try a couple of methods. First, sort your mailbox by fields like <strong data-start="119" data-end="145">Subject, From, or Date, and manually delete repeated items &mdash; useful for small mailboxes but time-consuming. Outlook&rsquo;s built-in <strong data-start="249" data-end="261">Clean Up tool can also remove redundant messages in a conversation or folder, but it doesn&rsquo;t always catch all duplicates, especially across folders or after sync/import issues.



<p data-start="433" data-end="885" data-is-last-node="" data-is-only-node="">For a faster and more accurate method, use a dedicated tool like <strong data-start="498" data-end="536">SysTools Outlook Duplicate Remover Software. It automatically scans PST/OST files, finds & remove duplicate contacts, calendars, and more, and removes them without harming your original data. You can also choose whether to check within a folder or across the mailbox and apply filters to clean specific date ranges. It's the most reliable way to keep your Outlook organised and duplicate-free.