Spam is a problem that everyone deals with in their inbox on a daily basis. Sometimes however, you see a message in your inbox that appears to be a message that was sent by you and was returned because the recipient’s address no longer exists or the message was rejected by a spam/virus filter. This is concerning because you know that you never sent the message in question. If you know that you didn’t send the message, then most likely the culprit is a spammer.
Spammers are notorious for using other people’s email addresses in the “From” field on the spam messages they are sending out. This is known as “spoofing”, or sending messages using a fake or incorrect return address. This causes any messages that don’t make it to the intended target to find its way back to your inbox rather than back to the spammers’. Spammers can get your address by using software programs that can scan the web to find email addresses in chat rooms, newsgroups, etc. Unfortunately there really isn’t much you can do to stop them since they’re not really sending through your account and because the spammers could be located anywhere in the world and are nearly impossible to track. Usually these types of messages are harmless but you should still exercise caution, especially if there is an attachment. Its generally a good idea to just delete any messages that appear suspicious.
It’s also possible that your email account has been compromised and that the spam is actually coming from you. If you suspect that this is the case you should change your email password ASAP to prevent any further unauthorized access to your account.
Another less-likely possibility could be that you have a virus that is spreading itself by automatically emailing itself to everyone in your address book. Keeping an up-to-date anti-virus program and never opening attachments in a suspicious email are the best ways to prevent this from happening. If you think this may be your problem, then you should run a full-system scan with your anti-virus to make sure that your computer is clean.