The reason for this is that MWES doesn't store duplicates of quarantined messages, because there’s no point in storing the same spam email (this is only specific to emails blocked by FirstAlert),but you will still see them in the tracking screen.
The quarantine only holds email for 7 days, but it’s actually cached in the background as a signature (until it reaches 20,000 emails in the cache, then the oldest blocked emails get dropped off).
You can change these parameters if you wish as below.
Windows users can add/change these options in the registry
Windows Registry: "HKEY_LOCAL_MACHINE\SOFTWARE\Firetrust Limited\mwes"or HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Firetrust Limited\mwes (64 bit OS)If changed, restart the MailWasher Enterprise Server Service (Go to Start>>Run>>Type 'services.msc' and locate MailWasher Enterprise Server, and restart).
Linux users can add/change these options in the mwes.conf fileLinux: /etc/mwes.confIf changed, restart service/daemon.
FirstAlert Cache: cfs_max_cache_size=20000
RBL cache: rbl_max_cache_size=20000
Quarantine days: (You’ll need to add these in)