Hello,
The Custom Reports and Scheduled Email Reports options were removed in SmarterMail 16 (16.0.6345 (May 16, 2017)) and newer. We found that less than 5% of the our users were using it. The Disk Usage information can still be grabbed at the domain level.
Thank you
Tony Scholz
System/Network Administrator
SmarterTools Inc.
www.smartertools.com