Mailbox to PDF documentation

Install Mailbox to PDF

Mailbox to PDF runs on macOS 14 Sonoma or later, on Apple silicon and Intel Macs. After buying, download the app zip from your Polar receipt, unzip it, and drag Mailbox to PDF to your Applications folder.

The app is signed and notarized by Apple. Confirm Open at the normal first-launch prompt.

The app works without a license key. The key in your receipt turns on automatic updates: enter it in Mailbox to PDF → License…. Once a day, the app checks for a new version, shows what’s new, and installs it with Install and Relaunch. Mailbox to PDF → Check for Updates… checks right away. A key works on 3 Macs. To move it to another Mac, choose License… → Deactivate This Mac first. Your receipt always has the latest version, too.

Bring the emails in

The window says “Turn emails into PDFs” and offers three ways in. Nothing is written until you click Save.

Emails selected in Mail

Open Mail and select the emails you want. Hold Command to pick several, or select a whole conversation. Then click Read Selected Emails in Mailbox to PDF.

The emails are copied to a temporary folder of the app’s own, and the list shows them under “Selected in Mail”. That folder is deleted when you quit the app.

If nothing is selected, the window says “No emails are selected in Mail”. Select them and click Try Again.

A mailbox in Mail

Click Choose a Mailbox…. The window lists the mailboxes of every account, with the ones on your Mac under On My Mac, and the number of emails in each. Pick one and click Read This Mailbox.

For a big mailbox the window shows how far it got, like “7,400 of 20,133 emails”. Stop goes back to the start. The list comes from the emails’ headers, and each email is read in full only when it’s saved.

Files

Click Choose Files…, choose File → Open… (⌘O), or drop them on the window. These work:

a mailbox exported from Mail with Mailbox › Export Mailbox… (a folder ending in .mbox);
an .mbox file downloaded from another mail service;
.eml files, the format Mail and most mail apps use when you drag an email to the Finder;
.emlx files;
a folder of any of them.

Files need no permission. A file that isn’t mail is left out, and a line under the list names it, like “1 file wasn’t read: Notes.txt. It isn’t a mailbox or an email file.”

When Mail asks for permission

The first time you click Read Selected Emails or Choose a Mailbox…, your Mac asks whether Mailbox to PDF can control Mail. Click Allow. The app only reads: it never changes, moves or deletes anything in Mail.

If you clicked Don’t Allow, the window says “Mail access is off”. Click Open System Settings, which opens Privacy & Security › Automation, turn on Mail under Mailbox to PDF, and click Try Again.

Pick the emails

The list shows the emails newest first, with a checkbox, a paper clip when the email has attachments, the sender, the subject and the date. A warning sign next to the subject marks an email that can’t be read as a whole: it’s still saved, as the text it was received as.

All of them start ticked. Untick the ones you don’t want, or use All and None.

To keep part of them, tick Only emails from and pick two dates. Both days are included whole. All and None act on the emails in the dates you picked.

The line at the bottom counts them, like “8 of 10 picked”.

Choose what to make

Choice	What you get
One PDF per email	A file for each email, named with its date and subject, like `2024-03-09 Invoice for March.pdf`
One PDF per conversation	A file for each conversation, named with its first date and its subject without “Re:”, the emails in order, each starting on a new page
One PDF for everything	One file named after the mailbox and the dates it covers, like `Lumen Studio 2024-03-08 to 2024-03-20.pdf`, each email starting on a new page

One PDF for everything takes up to 2,000 emails. Past that, the window says so and the Save button waits until you pick fewer or choose another layout. The other two have no limit.

Conversations come from the headers that say which email answers which, so a conversation that branches stays together. A reply sent by an app that leaves those headers out joins the conversation with the same subject.

Save attachments in a folder next to each PDF is on to start. Each PDF gets a folder with the same name, like 2024-03-11 Re Invoice for March, holding the files sent with its emails.

Load pictures from the internet is off to start. Many emails show pictures stored on the sender’s server, and loading them tells the sender you opened the email. Pictures sent inside the email always show.

Save

Click Save 10 PDFs… (the number follows your choices) and pick a folder. The window shows “Saving 6 of 10…”. Stop finishes the email it’s on and stops there.

Files already in the folder are never replaced. A new file with a name that’s taken gets a number, like 2024-03-09 Invoice for March 2.pdf. Names are cleaned so they work on a USB stick and on Windows. Every PDF, attachment and attachments folder is dated like its email.

Then the window says what happened, like “Saved 3 PDFs with 3 emails in Accountant 2024.” and “Saved 1 attachment.”, with the PDFs listed. Anything that wasn’t saved is listed with why, like “It couldn’t be turned into pages.” A PDF counts as saved only once it’s on disk and opens.

Show in Finder shows the PDFs. Back to the List keeps the same emails, to save them again another way. Start Over goes back to the three ways in.

What’s in the PDF

Each email starts on a new page with a block that has:


From	The sender’s name and address
To and Cc	Everyone it went to
Date	When it was sent, in your Mac’s language
Subject	The subject, or “(No subject)“
Attachments	The names of the files sent with it

Then the email as Mail shows it: the formatted version when the sender sent one, the plain text otherwise. Pictures sent inside the email show where they were sent. An email wider than the page, like a newsletter with a big table, is shrunk to fit. Long emails run over as many pages as they need. You can select and search the text in Preview.

An email that can’t be read as a whole, usually old or broken mail, is printed as the text it was received as, under the note “This email couldn’t be read as a whole … so here it is as it was received.” The window lists it after saving.

An email forwarded as an attachment is saved as an .eml file in the attachments folder, named after its subject.

Privacy

Everything stays on your Mac. The app reads only the emails you pick and writes the PDFs where you choose. Scripts in emails never run, and nothing in an email can reach the network unless you turn on pictures from the internet. Once a day the app sends its license key to my update server, updates.flaviocopes.com, to check for a new version, and about once a week it checks the key with Polar, the shop. There are no accounts and no analytics.

Troubleshooting

Mail access is off

Click Open System Settings in the window, turn on Mail under Mailbox to PDF in Privacy & Security › Automation, then click Try Again.

The paper clip was wrong

When you read a mailbox from Mail, the paper clip is a guess from the email’s headers, because the app reads each email in full only when it saves it. The attachments themselves are always saved.

It says “One PDF for everything takes up to 2,000 emails”

Pick fewer emails, for example with Only emails from, or choose One PDF per email or One PDF per conversation.

It isn’t a mailbox or an email file

Mailbox to PDF reads .mbox, .eml and .emlx files and mailboxes exported from Mail. To get a mailbox out of Mail, select it and choose Mailbox › Export Mailbox….

Mailbox to PDF isn’t made by, affiliated with or endorsed by Apple. Mail and Mac are trademarks of Apple Inc., used here only to say what the app works with.