How to Find Large Emails in Outlook Using size:>10MB

Why Outlook users search for size:>10MB

When an Outlook mailbox fills up, the fastest way to locate the problem is often the search operator size:>10MB. It surfaces messages with large attachments, old project files, ZIP archives, PDFs, and forwarded chains that quietly consume storage.

Finding the large message is only half the job. If you need to resend the attachment, forward it to another account, or share it with someone outside your organization, the same size limit can block you again.

  • Outlook.com and Microsoft 365 may reject large outgoing messages or suggest OneDrive links.
  • Corporate Exchange servers often have stricter limits than personal Outlook accounts.
  • Large forwarded threads can include several hidden attachment copies.

How to find large emails in Outlook

Use Outlook search first, then decide whether to archive, delete, download, or resend the attachment.

  1. Open Outlook or Outlook.com and click the search box.
  2. Type size:>10MB. For a broader cleanup, try size:>5MB; for very large messages, try size:>25MB.
  3. Sort the results by date or size and open messages that contain attachments you still need.
  4. Download the original file before deleting old email copies.
  5. If the file needs to be sent again, upload it to SendSplit instead of forwarding the oversized thread.

How SendSplit helps after you find a large attachment

Forwarding the old email may fail because Outlook counts the full message size, not just the visible file. SendSplit lets you send the original file as fresh, split attachments that fit the recipient inbox.

  1. Save the attachment from Outlook to your computer.
  2. Go to sendsplit.com/upload-to-send.
  3. Upload the file, choose a 10MB, 20MB, or 25MB split size, and enter the recipient email address.
  4. SendSplit delivers numbered ZIP parts as real email attachments, without forcing a OneDrive or cloud-sharing link.

When to use 10MB splits for Outlook recipients

Use 10MB splits when the recipient is on a corporate Exchange server, a government inbox, or an unknown Outlook configuration. It is the safest choice because many organizations reduce the default attachment limit below the public Microsoft value.

  • Use 10MB for corporate and unknown recipients.
  • Use 20MB when the recipient confirms Outlook accepts messages near 20MB.
  • Avoid forwarding huge Outlook chains; send the original file cleanly instead.

Common Outlook Search Variations

Outlook search is useful because you can adjust the size threshold to match your cleanup goal. If size:>10MB returns too many ordinary attachments, increase the threshold to size:>25MB or size:>50MB. If you are doing a deep mailbox cleanup before migration, try hasattachments:yes together with date filters so you can find old project messages that no longer need to stay in the mailbox.

Do not delete a large message until you have saved the original attachment somewhere safe. Once a message is removed from an Exchange or Microsoft 365 mailbox, recovery may depend on company retention settings.

Mistakes to Avoid When Resending Large Outlook Attachments

  • Do not forward the entire old conversation when you only need to send the file. Forwarded threads may include hidden copies of older attachments.
  • Do not assume Outlook.com and a company Exchange mailbox use the same size limit. Company administrators can set stricter rules.
  • Do not replace the file with a OneDrive link if the recipient cannot sign in or if the file needs to remain attached to the email record.
  • Do not choose a 25MB split size for a recipient you do not know. Use 10MB when reliable delivery matters.

Stop digging through old Outlook threads just to hit the same size limit again. Use SendSplit to resend large attachments as clean, email-friendly parts up to 200MB. Try SendSplit.