When comparing Mozilla Thunderbird vs ProtonMail, the Slant community recommends Mozilla Thunderbird for most people. In the question“What is the best desktop Email client for Windows 10?” Mozilla Thunderbird is ranked 1st while ProtonMail is ranked 9th.
Ranked in these QuestionsQuestion Ranking
Pro Free (as in freedom and beer)
Pro Lightning Calendar and Address Book integration
Pro Available on Linux, OS X and Windows
Pro Good filtering system
Mozilla Thunderbird offers a flexible filtering system with the ability to set flags and read/unread, as well as sort/assign to new mail directories. There are also numerous plugins available to assist in the filtering.
Pro Very reliable
Version after version, Mozilla Thunderbird works as expected.
Pro Consistent and involving a moderate learning curve
The app design of Mozilla Thunderbird has not changed significantly since its beginning, making its learning curve almost non-existent.
Pro Large assortment of plugins available
Mozilla Thunderbird offers a huge amount of extensions to expand the usability and options of the client.
Pro Tabs for navigation
Pro Send large files easy
Install pCloud plugin for Thunderbird and your files (upto 20 GB free storage included) will be received as download links
Pro Privacy respecting
User data is protected by strict privacy laws because all servers are located in Switzerland.
Pro Open Source
Pro Built-in end-to-end encryption
Pro No personal information needed
To create an account you don't need to give any personal information, just choose username, domain, and password. Even the recovery email address is optional.
Pro Overly Expensive for Desktop Support
Pro Mobile apps
Apps for Android and iOS available.
Con Terrible integration with macOS
Simple things - drag/dropping pictures doesn't work, for instance.
Con Development slowed to only focus on stability and security
Mozilla Thunderbird has slowed down its development of features to only focus resources on security and stability.
Con Subject lines can (temporarily) disappear from the list
This is sporadic behavior.
Con Serious bugs
Clicking on a subject line can bring up the wrong email.
Con Outdated interface
Thunderbird's interface is very outdated and unpleasant. It feels more like a Windows XP application than like a modern MacOS one.
Con Still lacks some useful features
At the moment, there is no calendar feature and contact management is quite poor. They will, however, start to work on it.
Con Overly Expensive for Desktop Support
Con No IMAP and SMTP support for basic accounts
Basic accounts are restricted to the Protonmail web client. Support for IMAP and SMTP is available with a paid subscription only, and as such with basic accounts it is not possible to send and receive email with external applications.