SYMPTOMS

Antivirus scratch directory contains orphaned files

In most cases, there is a Knowledge Base article recommending the number of MTA transfer threads that should be used to avoid this problem, custom or third party scanners may have issues being run concurrently that are not likely to be documented in the Knowledge Base or by the vendor.

CAUSE

Some antivirus agents can have issues when called concurrently.

SOLUTION

As such, those using antivirus scanners that have concurrency or orphaned process issues
(i.e. if under task manager there are instances of the anti-virus program still running) may want to consider validating the process timeout (how long MailEnable will wait until it terminates the command line scanner process).

This is done via the following registry setting:

Key Root: SOFTWARE\Mail Enable\Mail Enable\Agents\MTA\Filters
Key Name: Process Timeout
Key Value Type: DWORD
Key Value Meaning: Time-out interval, in milliseconds. Value of 0xFFFFFFFF,
negative value or non existent key = Wait Indefinitely

MORE INFORMATION

How to debug the antivirus support and the Mail Transfer Agent: http://www.mailenable.com/kb/content/article.asp?ID=ME020121

How does Antivirus Filtering work and how to configure it?: http://www.mailenable.com/kb/content/article.asp?ID=ME020056