The best free alternative to Thunderbird is Betterbird, which is also Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Thunderbird and loads of them are free so hopefully you can find a suitable replacement. Other interesting free alternatives to Thunderbird are K-9 Mail, Evolution, SeaMonkey and FairEmail.
Koma-Mail is an email client which is comfortable and has very handy functions. It does not need an installation, so that you can run Koma-Mail from your flash drive but, of course, also on your desktop.
Germany
EU
Pegasus Mail is a free, standards-based electronic mail client suitable for use by single or multiple users on single computers or on local area networks.
New Zealand
Clyton is an email client with advanced security and spam filtering features. Although priced for the general public, Clyton possesses the reliability and security required by businesses.
United States
Sup is a console-based email client for people with a lot of email. It supports tagging, very fast full-text search, automatic contact- list management, custom code insertion via a hook system, and more.
mu is a tool for dealing with e-mail messages stored in the Maildir-format, on Unix-like systems. mu's main purpose is to help you to find the messages you need, quickly; in addition, it allows you to view messages, extract attachments, create new maildirs, …
NetherlandsEU
A modern, lightweight and private email client for Windows and Linux. Unlimited IMAP accounts in one unified inbox, tracking pixels blocked by default.
ItalyEU
TrulyMail is an email client and a private messaging system, very feature rich (voice recording, script blocking, etc.).
United States
EmailTray is a smart email client and an email notifier for POP3 and IMAP email accounts, including Gmail, Hotmail, Yahoo mail and AOL. EmailTray intelligently ranks messages, prioritizes them into 4 Inboxes and alerts you only to the most important.
Mulberry is a powerful, easy to use electronic mail (email) and calendar program that allows you to send, access, and manage email and calendars. Mulberry also helps you manage other related information, such as contact information.
United States
Pandora Mail is Windows desktop e-mail client used to access POP3/IMAP mailboxes and to send mail via standard SMTP protocol.
Armenia
