When using the procedure steps DeleteUser() or DisableUser() on a user with a space in the name, such as "John Smith", the user is not disabled or deleted
This is a known issue. User names without spaces are not affected.
WORKAROUND / RESOLUTION
You can work around this by using the "ExecuteShellCommand()" step and running the "net user" command
ExecuteShellCommand() - net user "john smith" /del