Retrieving messages stored in a mail server and pending to be retrieved by a user is disclosed. A summary of the messages stored in the mail server and pending to be retrieved by the user is received at a terminal device of the user, each message associated with a unique identifier. At least one of the messages to be retrieved from the mail server is selected on the basis of the summary of messages. From the unique identifier associated with the at least one message an identifier valid for retrieval of the at least one message is determined, and a retrieval request with the identifier valid for retrieval is sent to the mail server. Upon receiving the retrieval request with the at least one identifier valid for retrieving the at least one of the stored messages, the mail server sends the at least one message towards the terminal device.