We had this issue too back in SM 16. We finally wrote a PS script that removed the files for us. Though, the spool never figured this out until a restart, then it would reset the counts.

Mind sharing the script? We basically deleted them 200 at the time. Took a few hours :(

Patrick and Christopher, thanks for bringing this up.  We'll have added it to our bugs list.  We'll update you when there's a fix in place.

Patrick, this issue should now be fixed.  I am opening a ticket with you, Patrick, to send the link to the custom 16 build with the fix.  The fix has also been moved into the latest version of SmarterMail and will be available in the next public release.

Thanks. I am currently using 

                        SmarterMail Enterprise
                        Build 6928 (Dec 20, 2018)
Is it fixed in this build? I assume this is version 17.x but it doesn't seem to list the number version anymore under about.

Patrick, 6928 is the latest SmarterMail version (formerly called SmarterMail 17).  I provided a link to a custom build in a ticket I created with you.  Either you can try that custom build or wait until the next public release of SmarterMail, which will include the fix as well.

Ok I can wait. Like I said I already manually deleted all those emails. Just would have been so nice to be able to one click it.

Patrick, we have released Build 6948 that includes the fix mentioned earlier.