After opening a message that contains an attachment, a paperclip icon with a small arrow will appear next to the sender's name in the message header. When clicked, this icon shows actions that can be performed on an individual attachment or all attachments at once. These actions include Open, Quick Look, Save As, Detach and Delete.
The Attachment Pane can be found at the bottom of the message window underneath the message body. Each attachment is represented as an icon that can be manipulated as if they were in the Finder or Windows Explorer. On Windows, a single attachment can be selected and saved with drag & drop; on Mac, this can be done with multiple attachments selected simultaneously. A Save button at the top of the section will allow you to save all attachments to a specified destination.
The Inspector Pane is yet another way to view attachments. Please see this article for more information.
Postbox also has a dedicated attachments view. Click the paperclip icon in the View toolbar group to view all attachments within all messages in the currently selected folder. You can also search for files within other folders and use advanced search criteria in the search toolbar. More information on document searches can be found in this article.
macOS Quick Look
On macOS, Quick Look allows you to view attachments without opening the associated application. For example, if a Word document is received, it can be viewed in its entirety by selecting it (single-clicking on the attachment in the Attachments Pane or Inspector Pane) and pressing the space bar.
On Windows, if an image attachment is selected, the space bar will open a Quick Look window similar to the Mac.
Quickly Attach Documents to a New Message in macOS
macOS users have an additional shortcut for attaching files to new messages. First, make sure the file is saved. Then, in the title bar at the top of the document window, drag and drop the document icon on top of the Postbox icon in the Dock.
Postbox will compose a new message with the file attached. This works in Microsoft Office, iWork, Adobe Reader, and Preview.
Note: The Postbox application must be running when this operation is performed.
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 that reminds you that you may have forgotten the attachment.
You can customize the words that trigger the attachment reminder in the Composition preferences window. Go to:
Settings (macOS) | Options (Windows) > Composition > General and select the Keywords button. Here you can delete, edit and add the keywords for 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 major U.S. broadband providers' online and phone help desks. You may have to contact your ISP’s help desk for a definitive number.
- 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 > Typing. Set the maximum threshold, and you will be warned when your message exceeds this threshold.
Where are Attachments Stored?
Attachments received or sent in emails are stored within the messages, which are stored in the email database files themselves.
If you have a message with an attachment, that attachment is stored within the message, wherever that message may reside. If you move the message to a different mail folder, the message and its attachment are moved there.
Within a message, you can "save" the attachment to the File System in the OS. Once that happens, the attachment is stored in two locations, 1) your email message and 2) the File System. You can customize the attachment location in Preferences | Options > Attachments.
You can also "detach" attachments from messages, which moves the attachment from the message and stores it in the File System.
Finally, you can "delete" an attachment from a message, but this does not store it anywhere in your File System.