Verify Mail attachments are attached

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In my use of Apple’s Mail program, I send lots of attachments. Reviews and images to the Macworld offices, photos to families and friends, spreadsheets for various projects to other parties, etc. So I end up writing lots of emails that look basically like this:

To: Tina From: Rob Subject: Spreadsheet of costs

Hey Tina! Attached to this email is that spreadsheet we were discussing. Please get back to me with any changes after you’ve had a chance to review it.

After I finish typing, I hit the Send button, and then wait for Tina to reply. Some length of time later, I find this in my inbox:

From: Tina To: Rob Subject: re: Spreadsheet of costs

Hey Rob … there wasn’t an attachment on that email you sent. Can you please re-send?

Doh! I can’t count the number of times I’ve sent off emails such as the above, failing to attach the attachment. At least, I used to do that regularly. But now, thanks to a free Mail plug-in and a couple of Terminal commands, such incidents are largely a thing of the past. (Mail has an unofficial plug-in feature that many developers have used to write useful additions—such as the powerful MailTags plug-in.)

The Attachment Scanner plug-in is the solution to the “no attachments attached” problem. Once installed, the plug-in sits quietly in the background until you press the Send button. When you press Send, the plug-in goes to work, scanning your text for “attachment” words, and making sure that there’s actually an attachment attached if such words are found. If there is, nothing happens—your message is sent as you would expect. But if you try to send a message that references attachments, without actually attaching your file, you’ll see this instead:

The plug-in works by looking for variations on the word attach , like attached or attachments . When it spots one, and doesn’t see an associated attached file, you get the alert sheet.

Installing the plug-in

To use a Mail plug-in, you must first tell Mail that you want to use its plug-in architecture. Open Terminal (in /Applications -> Utilities) and type these two commands (make sure Mail isn’t running):

	defaults write EnableBundles -bool true
	defaults write BundleCompatibilityVersion 2

Once you’ve done that, you need to install the plug-in. First navigate to your user’s Library -> Mail folder, and create a new folder named Bundles (it will only exist already if you have other Mail plug-ins installed). Expand the Attachment Scanner plug-in, and then move the AttachmentScannerPlugin.mailbundle file into the newly-created Bundles folder.

Launch Mail and test the plug-in by creating a new message to yourself. Put the word attach somewhere in the body, and then press Send. If everything is working, you’ll see the above sheet.


All Mail plug-ins rely on a private interface that Apple may choose to modify or remove at any time. It’s entirely possible that this plug-in will break the next time Apple updates Mail. If that happens, just remove the items from the Bundles folder, and you’ll be back to a stock Mail install. If you’re extra paranoid, you could run one more Terminal command to disable Mail’s plug-ins again:

defaults write EnableBundles -bool false

Despite the caveat, I’ve been using this plug-in since April, and have had no issues with it at all—and it’s saved me from silly attachment mistakes countless times since then!

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