Download Thunderbird 155.0.1 for Mac

Thunderbird 155.0.1 for Mac

MAC
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September 15, 2026

Free

Thunderbird for Mac is a , open-source email client that helps users manage multiple email accounts in one place. Developed by Mozilla’s community, it offers features like email organization, calendars, contacts, spam filtering,

and security tools. With customizable options and support for various email providers, Thunderbird provides a reliable alternative to web-based email services.

Thunderbird Overview

Thunderbird for Mac is an open source email and productivity client built by Mozilla and maintained by a dedicated community that prioritizes user control over everything else. It manages multiple IMAP and POP3 accounts simultaneously, handles encrypted email through OpenPGP natively, and extends its functionality through a rich add on ecosystem.

The interface is fully customizable from layout to toolbars to message display and everything persists locally without depending on any cloud service to function. Users who want the same privacy first approach extended to their passwords will find Bitwarden for Mac a natural companion,

offering open source password management with zero knowledge encryption that pairs perfectly with Thunderbird’s commitment to keeping your data under your own control.

Key Features:

Multiple email account management in one place
Native OpenPGP email encryption support
Built in calendar with CalDAV and Google Calendar sync
Contact management with CardDAV support
Unified inbox across all accounts
Powerful message filtering and search
Add on and extension ecosystem
RSS and Atom feed reader built in
Customizable interface layout and toolbars
Offline access to all emails and folders
Spam filtering with adaptive learning
Thread and conversation view support
Import and export for all major email formats
Open source with no data collection
Fully optimized for macOS Sequoia

What’s New in 155.0.1

Message rendering speed noticeably improved
Full macOS Sequoia compatibility confirmed
OpenPGP encryption handling more reliable
Calendar sync stability improved across providers
Bug fixes and performance improvements throughout

System Requirements

OS: macOS 10.15 or later
RAM: At least 2 GB
Storage: 200 MB of free space
Processor: Intel and Apple Silicon both supported

How to Install Thunderbird on Mac

Download Thunderbird for Mac 155.0.1 full version.
Open the DMG file.
Drag the app to your Applications folder.
Launch Thunderbird for Mac.
Add your email account and start managing your inbox.

How to Download Thunderbird Using Mac

Visit the official Thunderbird website.
Click Download for Mac.
Wait for the DMG file to download.
Open your Downloads folder.
Run the DMG file to begin installation.

Supported Websites

Thunderbird Official Website
Mozilla Official Page
MacUpdate
Softpedia
Fosshub
Filehorse
1000+ other trusted sources

Why Use Thunderbird for Mac?

Thunderbird for Mac puts your email back under your control in a way that no web client ever can. Every message stores locally, works offline, and never passes through a third party server you did not choose. The unified inbox handles every account you own in one clean view and the filtering system automates sorting with rules precise enough to handle any inbox volume.

OpenPGP encryption works natively without any external tool and the calendar integration means you never need to open a browser tab just to check your schedule. Users who want to protect their connection and hide their IP while accessing email and browsing will find Proton VPN for Mac a trusted addition, backed by Swiss privacy law,

independent audits, and an open source codebase that verifies every claim it makes. Thunderbird for Mac is the email client for people who take their communication and privacy seriously.

Thunderbird vs Other Email Clients for Mac

Feature	Thunderbird for Mac	Others
Native OpenPGP Encryption	Yes	Limited
Full Offline Access	Yes	Limited
Open Source	Yes	No
Add on Ecosystem	Yes	Limited
Multi Account Unified Inbox	Yes	Limited
Mac Optimized	Yes	No

Frequently Asked Questions

Here are the most asked questions about Thunderbird for Mac:

Thunderbird for Mac is not receiving emails from one of my accounts even though the settings look correct, what should I check?

Open Account Settings for the affected account and verify the incoming server port and security settings match exactly what your email provider requires. Gmail requires IMAP on port 993 with SSL and also needs Less Secure App access or an App Password enabled if two factor authentication is active on your Google account. Correcting either the port settings or the authentication method resolves the majority of missing email issues immediately without touching any other configuration.

Thunderbird for Mac is running slowly with a large inbox, how do I speed it up?

Open the folder that feels slow, go to the File menu, and run Compact Folders. Thunderbird for Mac stores deleted and moved messages as hidden entries until folders are compacted and large uncompacted folders are the most common cause of sluggish performance. Running a compact on your inbox and sent folders regularly keeps Thunderbird fast and responsive regardless of how many total messages your account contains.

Can Thunderbird for Mac handle Gmail correctly including labels and all mail behavior?

Yes with the right configuration. Add your Gmail account using IMAP and in the account settings set the server to imap.gmail.com on port 993. Gmail labels appear as folders in Thunderbird for Mac and the All Mail folder syncs your complete archive. Disable syncing the All Mail folder in subscription settings if you want to avoid downloading your entire Gmail history locally since that folder can be extremely large on accounts with years of accumulated email.