nPOPuk is an ultra-small, but comprehensive, e-mail client that runs on a wide range of Windows-based operating systems. nPOPuks development was based on nPOP, a program originally created by Tomoaki Nakashima.
The new nPOPuk offers a dramatically expanded feature set, but the data files are not backwards-compatible with the original nPOP. This accounts for the decision to change the name. nPOPuk was chosen as it was programmed and compiled by a group co-ordinated from the UK.

nPOP Features:.
1. An ultra small e-mail client (A typical initial installation takes less than 280kb of disk space)
2. Portability (May be run from flash memory devices, or a floppy disk as it does not write to the Windows registry and leaves no trace on the host computer.)
3. Clearly displays, and optionally logs, its communication with mail servers (Ideal for managing mail on the server, making easy the deletion of spam and preventing the need to download large file attachments simply to enable that or following mail to be read)
4. Operates with the following servers and protocols: POP3, APOP, SMTP, SMTP-AUTH and SSL / STARTTLS (The last requires additional DLL files be installed with the program file)
5. Support for multiple accounts (together with multiple mail boxes (folders) for saving mail)
6. Complex mail filter facilities available for automatic processing of mail waiting on the server (Includes: rejection, acceptance, deletion, copying and moving of mail between Mailboxes)
7. Automatic checking for new mail at a user-defined frequency
8. An optional threaded display of mail
9. Provision of a simple address book
10. A choice of connection methods, including LAN and Dial-up

nPOPuk is a simple program to install to install and set up. Just download the ZIP file and open it, copy the program file to a suitable location and run it. When you do this for the first time, the Account Settings dialogue will open, where you can complete all necessary settings.

There are two kinds of Mailbox - Accounts and Saveboxes.
An account is a Mailbox that links with remote SMTP and POP3 servers. It is through these that mail is sent and received. Incoming mail deleted from an account will be deleted from the server. Similarly, if another program deletes mail from a server, then that mail will also be deleted from the account after nPOPuk next synchronises with the server.

A Savebox is a Mailbox to which mail can be moved or copied as, or after, it is retrieved from the server. A Savebox has no direct link with a remote server. Mail in a Savebox will be retained after the copy at the server is deleted.

nPOPuk is a true client/server application so does not work in the same way as a typical e-mail program. Mail is read directly from the server, not automatically deleted from it and, initially, held only in memory rather than saved to disk before being displayed.

The license of this software is Freeware, you can free download and free use this email checker software.