Roundcube webmail is an Internet Message Access Protocol, or IMAP, compatible interface that allows users to view and access their email on a server instead of downloading it to a computer email program first. Although Roundcube has many basic email features, it doesn't offer filter-style email address spam control that automatically transfers email from certain addresses directly into the Junk or Trash folders. As a result, controlling spam in Roundcube is a manual process -- you must physically move the messages out of the inbox.
Log into Roundcube to access your inbox. If the Inbox isn't open, click "Inbox" on the Folders left sidebar.
Click any message in the Inbox to select it. When selected, the message title bar turns red.
Click and drag the message to the Junk folder on the left sidebar or click the "Mark as Junk" icon above the Inbox area to transfer the message to the Junk folder.
Press and hold "Shift" on your keyboard and click more than one spam message title bar to group spam messages in the Inbox together to transfer multiple messages into the Junk folder at one time. After you select all of the messages, click and drag the group to the folder or click the "Junk" icon.
To delete spam messages, transfer the spam to the Trash or Deleted Items folder instead of the Junk folder. The messages automatically clear from the folder when you log out.
If your messages don’t clear, log into Roundcube, click “Personal Settings,” click “Server Settings” on the left sidebar and then confirm that the box to the right of “Clear Trash on Logout” in the Maintenance section has a checkmark in it. If it doesn’t, click the box, click “Save” and try again.