Sending Attachments

Attachment Reminders

It's a common occurrence. Forgetting to attach a file can be quite embarrassing. Fortunately, the Attachment Reminder feature in Postbox helps prevent this from happening. Here's how:

Mentioning certain words like "attachment", "enclosed" and "pdf" will cause Postbox to bring up an attachment pane at the bottom of the Compose window. Attempting to send the message without attachments will prompt a confirmation dialog which reminds you that you may have forgotten the attachment.

Customizing the Attachment Reminder

You can customize the words that trigger the attachment reminder in the Composition preferences window. Go to:

  • Preferences > Composition (or Tools > Options > Composition on Windows) and select the Keywords button. Here you can delete, edit and add the keywords for the Attachment Reminder.

Disabling the Attachment Reminder

If you prefer to disable the attachment reminder completely, go to Preferences > Composition (Tools > Options > Composition on Windows) and uncheck the option to check for missing attachments.

Attachment Size Limits

Attachment size limits are determined by your internet service provider and often by other gateways like in-house mail servers.

Like most policies of large communications services providers, e-mail file size limits are difficult to find and interpret. Many ISPs change their rules depending on the level of subscriber service. We assembled the list below from online and phone help desks at major U.S. broadband providers. For a definitive number, you may have to contact your ISP’s help desk.

AT&T: 25 Mb (webmail), 10 Mb (client)
Cable One: 10 Mb
CenturyLink: 10 Mb
Charter: 10 Mb
Comcast: 15 Mb
Cox: 10 Mb
EarthLink: 10 Mb (webmail), 5 Mb (client)
Frontier: 3 Mb
Gmail: 25 Mb
Qwest: 10 Mb
Time Warner Cable/Road Runner: 20 Mb
Verizon: 8 Mb (webmail), 20 Mb (client)
Bright House Networks/Road Runner: 20 Mb
Windstream: 1Gb
Optimum Online/Cablevision: 20 Mb

The message size indicator will display the total message size, including text and images.


You can set Postbox to warn you if you exceed this threshold in Preferences | Options > Composition > Advanced. Simply set the maximum threshold, and you will be warned when your message exceeds this threshold.