Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
Roundcube - Web-based IMAP email client
Axcrypt - AxCrypt - Password Protect Files With Strong Encryption. AxCrypt is the leading open source file encryption software for Windows.
Mailo - Mailo is an email client where you can send and receive emails to and from anyone with an email address.
Windows BitLocker - This topic provides a high-level overview of BitLocker, including a list of system requirements, practical applications, and deprecated features.