- An active iCloud account is required.
- Attachments don't count against your iCloud storage.
- Attachments expire after 30 days.
- You can't send a folder full of attachments; you have to compress the folder first.
- A single message and all attachments can't be more than 5GB.
- Whatever your attachment may be, you still have to wait for it to finish uploading to iCloud before recipients can download it.
Once you know MailDrop is for you, the first thing to do is make sure it is enabled. Go to Mail > Preferences > Accounts and in the Advanced panel make sure you have the box checked for “Send large attachments with Mail Drop.”
Remember, this checkbox shows on any IMAP account.
Here's the magical thing: Remember I said you needed an active iCloud account? You do, but you can use Mail Drop with any email account you have set up. That checkbox appears on all IMAP accounts as an option, iCloud or otherwise.
When you have that large attachment ready to go, you can send it using Mail. You could also use the iCloud webmail client but our example will be shown in Mail.
After verifying the box is checked for the account you want to use, just create a new message and attach a giant file however you normally attach a giant file. Drag and drop, click the paperclip, menu option, whatever. Get a message with a giant file attached:
Here's that message with a giant attachment. You can have as many as you want as long as they aren't grouped in a folder and don't exceed 5 GB.
And then we get to the part that makes it not very exciting: You hit send and you're done. On the other side the recipient gets a message with a download link (that expires after 30 days), and that's that. It's pretty straightforward, and it doesn't do anything different than before, except save you from ISP limits on attachment size and making your “Sent Mail” folder smaller since these attachments aren't cluttering it up.
There's no mucking about with Dropbox or logging into some sharing site or worrying about if the recipient checked email on their phone or computer. It's just a link in an email message which also keeps you from inadvertently taking down someone else's inbox (or even a company mail server) with a giant unexpected attachment.