I do not see this in any of the SMGs I support.

my first check would be DNS, perhaps slow response 

No, Thomas, I doubt.

If it is a single SMG instance, DNS is not really involved.

If there is only one entry in message tracker, but multiple entries in quarantine, then it seems to be an internal issue. I have checked different queuing directories, but no suspicious files (if you remember, there was a similar problem some builds before. The problem was caused by wrong file system rights. But here all rights are set in the right way).

I experience this issue in two cases after upgrading to the latest version. However I did not check other SMG environments so far, because I was to busy to keep quarantine database small.

Hi Diethmar,

I had the same behaviour on my own SMG a lot of month ago. The quaratine then grew and grew until all the disk space where filled up.

the only solution for me was to delete the quarantine database.

That's not a solution here, Heiko.

There are mails inside which will be needed I think. I use a paper called "TID Remove Duplicate Quarantine Entries" which has been written by Georg Duees. Unfortunately it seems to be not public.

Just now I have turned off a combination of activities for confirmed spam. "Quarantine" but do not create a digest for these entries. This combination did not have problems for many months. But after last update SMG stumbles ...

I will come back with more details, if support is able to find a reason (quarantine log shows some entries many, many times).

Turning off this combination does not change behavior .... 

I followed this tip again: https://portal.microfocus.com/s/article/KM000004408

I did it before more than one time. I even created a new in_queue directory owned by smg:smg. Nothing helped ..

However I used Pam's TID and this time it seemed to help by magic.

So if you are in the same situation, reset owners not only once if you are in trouble!