IT departments blame "the Internet," but usually when email is lost, it is due to incompatible systems and human error behind the scenes. Although the Internet is a dangerous place for a lone email message, there is hope of recovery for most lost email.

Miscommunication
To users, email is like the telephone. It's ubiquitous, easy to use, always available, and generally reliable. Sometimes with the telephone, however, the call doesn't go through. Maybe it's the wrong number. Maybe the circuits are busy. Perhaps the number has been changed or disconnected, or you have the wrong area code. What some users may not realize is the same things can apply to email messages.

With email, a system may be too busy to send a message for several hours. You may have an incorrect email address, an account may have been deleted, an address may have been changed, or you may have the wrong Internet domain name. These common problems cause email messages to be returned to the sender with an often-cryptic explanation of what went wrong. Sometimes, however, email messages don't "bounce." Instead, they seem to simply disappear.

Email's treacherous journey
While the telephone network is consistent in the technology that makes it up, email is a patchwork of fundamentally different technologies. If you have a cell phone, you may notice that, while driving, you sometimes lose your connection when moving between "cells." A similar situation occurs in the email world.

Email travels from point to point in a series of "hops." Often, an email message will actually pass from one kind of email system to another with each hop. Unfortunately, not all email technologies are created equal, and the multiplicity of email systems can make the journey tremendously complex behind the scenes.

The main cause of "lost" mail is that each email technology uses a different kind of address. When an email message travels between different systems, it may pass through gateways that link two or more fundamentally different email systems together. Gateways have to rewrite or map addresses from one system, such as the Internet, to another system, such as Microsoft Exchange, and then back again. This process is often fraught with errors, and it is the primary cause of lost email.