We discovered that *Claws Mail*, the email client in Tails, stores plaintext copies of all emails on the remote IMAP server, including those that are meant to be encrypted.
When sending an email, *Claws Mail* copies the email in plaintext to the sending queue of the IMAP server before encrypting the email.*Claws Mail* deletes this plaintext copy after sending the email.
Automatically if you selected the **automatically save message to Draft folder** option in the writing preferences. This option is deselected by default in Tails.
To know if you are using IMAP or POP, choose <span class="menuchoice"> <span class="guimenu">Configuration</span> ▸ <span class="guimenuitem">Edit accounts…</span></span> and refer to the <span class="guilabel">Protocol</span> column in the list of accounts.