Filename Extensions
If you are seeking information about file extensions, then you are in the right place at right time.

Details of extension .letter

1 extension(s) and 0 alias(es) in our database

Below, you can find answers to the following questions:

  • What is the .letter file?
  • Which program can create the .letter file?
  • Where can you find a description of the .letter format?
  • What can convert .letter files to a different format?
  • Which MIME-type is associated with the .letter extension?
Sendmail Undeliverable Mail .letter file icon

Sendmail Undeliverable Mail

LETTER file is a Sendmail Undeliverable Mail. Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.
Detailed description not available
Category: Other files
Application: Sendmail
Program name: -
Mime-type: application/octet-stream
Magic bytes (HEX): -
Magic string (ASCII): -
Related extensions:

Other types of files may also use the .letter file extension. If you have helpful information about .letter extension, write to us!

Can't open a .letter file?

If you want to open a .letter file on your computer, you just need to have the appropriate program installed. If the .letter association isn't set correctly, you may receive the following error message:

Windows can't open this file:

File: example.letter

To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select from a list of programs that are installed on your computer.

To change file associations:

  • Right-click a file with the extension whose association you want to change, and then click Open With.
  • In the Open With dialog box, click the program whith which you want the file to open, or click Browse to locate the program that you want.
  • Select the Always use the selected program to open this kind of file check box.

Supported operating systems

Windows Server 2003/2008/2012/2016, Windows 7, Windows 8, Windows 10, Linux, FreeBSD, NetBSD, OpenBSD, Mac OS X, iOS, Android

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