How to Send Large File Attachments (Up to 5 GB) in OS X Mail

Computer on desk
Flickr/Aleksi Tappura

Using OS X Mail and iCloud Mail Drop, you can send files up to 5 GB in size easily by email.

Is Bigger Better for Attachments?

If a file and image of, say, 3 MB are fabulous to send and receive by email, are a video and folder of 3 GB 1000 times as marvelous to get and deliver? As anybody who ever tried to attach (or even send) a file too large for email has likely found out, they are not.

Instead, big files cause delays, waiting, errors, repetition and undelivered messages, not to mention unspeakable frustration, (verily) struck keyboards and strained relationships.

You can, of course, go hunting for services and plug-ins and apps. Is there an easier way, though, to deliver those 3 GB (and more perhaps) with joy (and, as far as I can tell, secure privacy to boot)?

iCloud Mail Drop to the Large Attachment Sending Rescue

In Apple OS X Mail, there is: using an iCloud account and a service dubbed "Mail Drop", OS X Mail can automatically upload files deemed too big to fit into many an email service's message and attachment size restrictions to iCloud servers, where they are available for easy pickup by any recipient during 30 days. Of course, the documents are stored on the server in encrypted form.

To you as a sender, Mail Drop attachments operate no different from attachments sent directly with the message; to recipients using OS X Mail, Mail Drop attachments present as regularly attached files as well (no need to download files manually using a browser).

Send Large File Attachments (Up to 5 GB) in OS X Mail

To send files up to 5 GB in size via email from OS X Mail:

  1. Make sure Mail Drop is enabled for the account you are using. (See below.)
  2. Use one of the following methods to add files and folders to a new message, reply or forward you are composing in OS X Mail:
    • Position the text cursor where in the message body you want the attached files to appear; click the Attach a document to this message icon (sporting a paper clip, 📎) in the message's toolbar; highlight the desired document, documents or folder or folders you want to attach; click Choose File.
    • Make sure the cursor is where you want to insert the file or files; select File | Attach Files… from the menu or press Command-Shift-A; select the desired files and folders; click Choose File.
    • Drag and drop the desired document or folder onto the message body (where you wish the attachment to appear).
  1. For attachments exceeding a certain size depending on your email provider but typically around 5–10 MB and up to 5 GB for individual files or the sum of all attachments per message (whichever is bigger), OS X Mail will automatically:
    • Upload the file in the background to an iCloud web server where recipients can pick them up following links in the message.
    • Keep the files available for download for 30 days.
    • Insert small versions for images with the full version available for download.
    • Automatically download Mail Drop attachments (so they appear just like regular attachments) for recipients that use OS X Mail as well.

Enable Mail Drop for an Email Account in OS X Mail

To turn on Mail Drop so large attachments sent from an OS X Mail account are automatically processed using Mail Drop:

  1. Make sure you do have an iCloud account and you are signed in to it with OS X Mail.
  2. Select Mail | Preferences… from the menu in OS X Mail.
  3. Go to the Accounts tab.
  4. Select the account for which you want to enable Mail Drop in the accounts list.
  5. Open the account's Advanced settings category.
  6. Make sure Send large attachments with Mail Drop is checked.
  7. Close the Accounts preferences window.

(Updated March 2016, tested with OS X Mail 9)