MailEssentials may sometimes quarantine internal email messages that have attachments showing "corrupted archive found". The filter that blocks the emails is the Decompression Engine.
Email attachments will occasionally be blocked and moved to the quarantine if there is a third party anti-virus or backup software running on the MailEssentials server and scanning the GFI directories.
This linked article on "Emails containing Microsoft Office attachments blocked as containing corrupt archives" explains in detail the root cause of the issue, and recommends to follow the instructions in the Recommended Antivirus and Backup Exclusions article to solve the issue.
Alternatively, you can disable the "Check corrupted archives" as described in the "Corrupted Archives Are Blocked by GFI MailEssentials" article while noting that this action may be a security risk.
After applying the steps above, internal emails should flow correctly and not be quarantined.
If the issue still persists, please generate the troubleshooting logs as follows:
- Make sure that you have tracing enabled.
- Wait for at least 30 minutes to gather enough information and for the issue to be reproduced.
- Run the troubleshooter:
- Start > Programs > GFI MailEssentials > Troubleshooter
- Follow the Log Generation Wizard for collecting the required and pertinent information.
- Select New Case when completing the log generation to attach the logs to a new case that will be automatically created, or open a support ticket manually and attach the logs to that ticket, so that the Support team can investigate the problem.