Jira is creating issues from previous emails in mail server that have already been read

[t]

is there a way to get JIRA to create issues from only new unread emails from the mail server? not ones that are existing already..

[Piotr Klimkowski]

By default JIRA processes all messages that with DELETED flag set to false. Once they're processed by mail handler they're marked as deleted. Default mail handlers do not take the SEEN flag into account. Possibly some 3rd party mail handler could do that. Alternatively you might want to create custom mail handler that processes only unread messages.