A setting needs to be in User Profiles in order to rectify this issue.
Note: If you or your system administrator don't have access to User Profiles, please raise a new case online and reference the title of this article.
Go to user profiles.
Open relevant user.
Go to Case General tab.
Amend 'When opening Proclaim Desktop, go to this tab first' from Mailbox to Today's Cases.
Click Save.
Get user to login to Proclaim again.