Apple Mail vs. Thunderbird in 2026: Which Is Better on Mac?

For most people on a Mac in 2026, Apple Mail is the better pick: it syncs with your iPhone, sorts mail into categories, schedules and unsends messages, and adds Apple Intelligence summaries. Thunderbird is better if you need OpenPGP encryption, deep filters and add-ons, one app across Mac, Windows and Linux, or a Microsoft 365 account Mail can no longer reach.

That last point is new this year, and it changes the answer for a lot of work accounts. Microsoft started switching off the old connection Mac apps use for work mail, and the two apps are handling it differently. I read most of my mail on my phone between meetings, so iPhone sync usually settles the question for me, but not for everyone. Below: a side-by-side table, the Microsoft 365 situation, features, privacy, devices, cost, how to switch, and a quick way to choose.

Apple Mail vs. Thunderbird at a glance

Apple Mail is Apple's own email app, included with macOS. Mozilla Thunderbird is a free, open-source email client from the Thunderbird project, funded by donations. Here is how they line up on a Mac today.

Which is better for most Mac users?

Apple Mail is the better default for a Mac user who also carries an iPhone, because Mail on the iPhone is the same app with the same accounts. Rules you create in Mail also sync to your other Macs when iCloud Drive is on with Mail selected, as Apple's rules guide explains.

Thunderbird earns its spot when the job is bigger than a personal inbox. I keep it for the times I need to encrypt a message to someone who uses PGP, or when I want one filter setup that works the same on a Windows machine. If neither of those sounds like you, Thunderbird will mostly feel like a second app to maintain.

The honest exception in 2026 is a work Microsoft 365 account. That deserves its own section.

Exchange and Microsoft 365: the difference that matters in 2026

Microsoft began blocking Exchange Web Services (EWS) in Exchange Online by default on October 1, 2026, with a final shutdown planned for April 1, 2027, according to BleepingComputer's report on Microsoft's guidance. Apple Mail on Mac uses EWS for Microsoft 365 accounts, so it depends on your administrator until Apple ships a fix.

Apple's support article says that if Mail, Calendar, Contacts, Notes or Reminders on your Mac stop syncing with Exchange or won't sign in, you should contact your Exchange administrator. An admin can keep Apple's apps working for now by adding Apple Internet Accounts to the EWS allow list. Apple says it is working with Microsoft to move these apps to the Microsoft Graph API "in a future update to macOS 27", with no date given.

Thunderbird already has that route for mail. Thunderbird 145 added native Exchange email over EWS (Thunderbird's announcement), and Thunderbird 154 on the Release channel added Microsoft Graph, per the Thunderbird blog's Graph post. Two caveats from that same post: the Extended Support Release (153 ESR) does not include Graph, and neither EWS nor Graph syncs your Exchange calendar or contacts in Thunderbird yet.

How to add a Microsoft 365 account to Thunderbird with Microsoft Graph

1. Open Thunderbird and choose Thunderbird > About Thunderbird from the menu bar. Make sure you're on version 154 or later, not the 153 ESR.
2. If you already added the account as Exchange (EWS), remove it in Account Settings. Thunderbird can't convert it, and removing it doesn't touch the mail stored in Microsoft 365.
3. Add the account again with your Microsoft 365 address. The Account Hub should detect it and offer Microsoft Graph.
4. Sign in on Microsoft's own page when it opens; your password goes there, not into Thunderbird's setup form.
5. If automatic setup fails, follow the manual steps the Thunderbird team links to, and ask IT whether your organization requires a custom app registration.

When my work account started asking for my password over and over in Mail, the useful move was a two-line message to IT asking which client they support, not reinstalling anything. Do the same before you switch: some organizations will allow Apple's apps, some will push you to Outlook, and some will be fine with Thunderbird over Graph.

Everyday features: what each app does without add-ons

Apple Mail covers more of the daily basics out of the box, while Thunderbird leaves several of them to add-ons. The gap shows up most in sending, sorting and AI.

Scheduling, undo send and reminders

In Apple Mail, click the small pop-up menu beside Send and pick a time, or choose Send Later for a custom date; scheduled messages wait in the Send Later mailbox (Apple's sending guide). Undo Send appears low in the sidebar for 10 seconds after you send, or use Edit > Undo. Change the window in Mail > Settings > Composing > Undo send delay.

Apple Mail also brings messages back on its own. Remind Me pushes an email back up your inbox at a time you pick, and Follow Up Suggestions resurface a sent email with no reply after three days, turned on or off in Mail > Settings > General (Apple's revisit guide).

Thunderbird has no built-in scheduler of this kind. The popular fix is the Send Later 3 add-on, which adds a dialog for a date and time. Thunderbird has to be open at that moment for the message to go, so it's a poor fit for a laptop that's closed overnight. When I write a Sunday-night note to my team that I want in their inbox Monday at 8 a.m., that detail alone keeps me in Mail.

Sorting, rules and filters

Apple Mail sorts incoming mail into Primary, Transactions, Updates and Promotions. To move a sender, Control-click one of their messages and choose Categorize Sender; to turn categories off, choose View and clear Show Mail Categories (Apple's categories guide). Apple says categories are offered in some countries and regions only. For anything categories can't do, rules in Mail > Settings > Rules can move, flag, reply to or delete messages, and can even run AppleScript.

Thunderbird's message filters, tags and add-ons go further for people who like to build their own system, and the Thunderbird homepage pitches exactly that: filters, tags, a unified inbox and extensions. The catch: those filters run on your computer. A long-running request on Mozilla Connect points out that Thunderbird's filters don't sort mail while the app is closed, so server-side rules at your mail provider are still the better place for anything that must happen around the clock.

AI features

Apple Mail has Apple Intelligence on Macs with M1 or later: short summaries under unread emails, a Summarize button at the top of a message or thread, Smart Reply suggestions when you click Reply, and Priority Messages under View > Show Priority Messages (Apple's guide to Apple Intelligence in Mail). It isn't available in every language or region.

Thunderbird's standard release doesn't list built-in summaries or reply suggestions. If AI drafting matters to you, Mail has it today, and a separate assistant can cover either app (more on that below).

Privacy and encryption: Apple Mail vs. Thunderbird

Both apps stop senders from learning much when you open an email, but they do it differently, and only Thunderbird supports OpenPGP encryption.

• Apple Mail: with Protect Mail Activity on (Mail > Settings > Privacy), your IP address is hidden from senders and remote content downloads in the background when the message arrives, not when you open it (Apple's privacy guide). Turn it off and you can hide your IP address and block all remote content separately.
• Thunderbird: remote content is blocked by default, and a bar on each message lets you load it for that message or allow a sender (Mozilla's remote content article).
• Encryption: Apple Mail signs and encrypts with personal certificates in your keychain, the S/MIME standard, and shows a lock only when it has a certificate for every recipient. Thunderbird has OpenPGP built in and supports S/MIME too (Mozilla's OpenPGP guide).

In practice, S/MIME is what corporate IT hands out, and PGP is what journalists, security folks and privacy-minded contacts use. The day a contact sent me their public key and asked me to reply encrypted, Thunderbird was the only app on my Mac that could do it without a plug-in.

iPhone, iPad and other devices

Apple Mail runs on Mac, iPhone and iPad and nothing else. Thunderbird runs on Mac, Windows and Linux, and on Android through Google Play and F-Droid, per the Thunderbird site.

There is no Thunderbird for iPhone yet. The team published a first look at the iOS app on October 1, 2026, and said it aims to have a first version ready for community testing in the next few months. Until it ships, a Mac-plus-iPhone setup with Thunderbird means two different apps with two different sets of habits.

If you work on a Windows PC in the office and a Mac at home, flip that logic. Thunderbird is the one app that looks and behaves the same on both.

Calendar and contacts

Thunderbird keeps mail, calendars and contacts in one window, which the Thunderbird site lists as a core feature. Apple splits them into Mail, Calendar and Contacts, which share your accounts through macOS.

For a personal or Google account, either approach works. For a Microsoft 365 work account, neither is great this year: Thunderbird doesn't sync Exchange calendars yet, and Apple's Calendar uses the same EWS connection as Mail. If your day runs on a Microsoft 365 calendar, check with IT what they support before moving anything.

Look, feel and updates on a Mac

Apple Mail looks and behaves like every other Mac app because it is one: standard toolbar, sidebar, swipe gestures, Command-comma for settings. Thunderbird uses Mac menus and shortcuts too, but its layout and settings pages are Mozilla's own, so it feels like the same app on every platform rather than a Mac-first one.

Updates arrive differently. Apple Mail updates with macOS. Thunderbird moved to monthly releases as its default in 2025 (Thunderbird's 2025 review), with a slower Extended Support Release for people who want fewer changes. Thunderbird 153 ESR needs macOS 10.15 or later (system requirements), so it's also a way to keep a modern, maintained mail app on an older Mac that can't run the latest macOS.

Cost

Both are free. Apple Mail comes with every Mac. Thunderbird is free to download and says it's funded by user donations (Thunderbird site). The Thunderbird team has said its planned Thunderbird Pro services will be optional paid subscriptions and that the desktop and mobile apps stay free (Thunderbird's 2025 review).

How to switch from Apple Mail to Thunderbird on a Mac

Switching is mostly painless for IMAP, iCloud and Gmail accounts, because the mail lives on the server and appears in Thunderbird once you sign in. The work is in local folders and rules. Before I change mail apps, I export every On My Mac mailbox first, because those exist only on that computer.

1. In Apple Mail, select the local mailboxes you want to keep and choose Mailbox > Export Mailbox. Mail saves each one as an .mbox package (Apple's import and export guide).
2. Install Thunderbird and add your accounts. Server-based mail downloads on its own.
3. Install the ImportExportTools NG add-on, which imports mbox files, including folder structure, into Thunderbird.
4. Import the .mbox files into a local folder in Thunderbird and check a few messages and attachments.
5. Rebuild your Apple Mail rules as Thunderbird message filters. They don't carry over.
6. To make Thunderbird open when you click an email link, open Apple Mail, choose Mail > Settings > General, and pick Thunderbird from Default email reader (Apple's General settings guide).

Going back from Thunderbird to Apple Mail

The reverse works the same way. Export local folders from Thunderbird as mbox with ImportExportTools NG, then in Apple Mail choose File > Import Mailboxes, select Files in mbox format, and find the messages in a new mailbox named Import (Apple's import and export guide).

Apple Mail or Thunderbird: which should you choose?

Choose by the one requirement you can't give up, not by the longest feature list.

If you're comparing more widely, our Gmail vs. Apple Mail guide covers the web-first option, and the Spark alternatives page looks at Apple Mail and Thunderbird next to paid clients.