My old office contacted me asking about a folder named NotSpamtraining that has grown to 24GB. This folder is not familiar to me. What is this folder and what adds to it? They are using POPFile.

Hi Brian,
Did you ever have any spam filter software in place? We are still using Spamhalter which is integrated in Mercury. When anti spam software is in place, it's using different additional folders for sorting out spam, or learning after classifying a mail as false positive or missed spam.
With us we have the following procedure:

• Spamhalter is checking each mail and is classifying a mail by an additional mail header
• A Mercury filter is searching for that additional mail header
• In case the mail header value exceed a predefined value, the filter is sorting out the mail and move it into our SPAM folder, which is a separate "user" account
• For false positives we got an additional account "NO_SPAM" in place where mails from the SPAM account can be move to. Spamhalter is regularly checking this folder for adjusting its database.
• For missed spam which is reaching the user accounts, we got the additional mail account "IS_SPAM" in place. Users may forward such mails to that account. Spamhalter is also regularly checking this account for learning purposes as well.

Spamhalter is intelligent enough to avoid an exceptional growing of its database. Nevertheless an anti spam software should bring any tools for tidy up its database with it.

It seems anybody has installed a spam software at your mail server after you left the office. Unfortunately I don't know something about POPfile.
Nevertheless 24 GB seems to be too big for a database. Our spamhalter database is about 5 MB in size.
Maybe your "NotSpamTraining" folder doesn't contain the spam software database but is the folder where spam is automatically moved to. In case this folder is not automatically checked and emptied, someone should check and delete it manually and regularly.

With us, our secretary and me are trying to check the "SPAM" account once a day to check whether any false positives are mistakenly trapped in. When closing the SPAM account an additional filter is automatically deleting all mails which are older than 30 days.

Thank Joerg. I will be going to the office this morning to try to figure it out.

I figured it out, and I can be such a bonehead sometimes. A few months before I retired there was serious discussion about switching from POPFile to Spamhalter. That change never materialized but in preparation for it I had added a filtering rule to collect messages for training. That rule copied all non-spam messages to a folder named NotSpamtraining It was supposed to be in place temporarily. We now know how that worked out. There needs to be a smiley indicating slapping yourself in the head.

Welcome in my world. The older I am the more things of the short time memory in my head are getting lost from one day to another.

But the more perturbing thing is that it seems nobody else in your old company has a clue how Mercury & Co. are working. At least I have a colleague here with us who has been familiarized with Mercury and Pmail. But I guess as soon as I leave the company, at least Pmail will be immediately replaced by other mail clients. But Mercury could survive since other solutions like MS Exchange are often too complicated to admister, especially for small companies without dedicated IT department.

BTW, for spamhalter there is no need to collect "good" mail for training purposes. Instead you should collect the real spam to train the database. But the original database which comes with the first setup, is good enough to start.