xuser [-U <user_key>] [-c <os_user>\<domain>] clear
In order to delete all XUSER entries assigned to your operating system user, do not specify any options.
XUSER is not a tool for managing database users or Database Manager operators. It only manages XUSER entries for these users in the XUSER program. Deleting an XUSER entry does not mean the corresponding user is also deleted. To delete users, use the Database Manager database tool.