Addressing Error: Virus scanner reports invalid condition errors in the AntiVirus logs and email being held in the Holding Queue

If you are encountering Error: Virus scanner reports invalid condition errors in the \MDaemon\Logs\MDaemon-YYYYMMDD-antivirus.log and email is being held in the MDaemon holding or local queue rather than being processed correctly then please take the steps below to address this.

The usual cause is either a corrupt antivirus definitions update has been downloaded by the AntiVirus Engines and is causing local and remote queue processing issues or a third party antivirus software is acting on the definition files and damaging them.

1. Confirm any third party antivirus software installed on the MDaemon machine is not configured to scan the MDaemon folder.
   
2. Attempt a manual antivirus definitions update via Security -> Antivirus -> AV Updater -> “Update AV signatures now” then allow MDaemon to process the holding queue automatically or right click the holding queue and choose Re-Queue to pass the email back through the antivirus scanner.

If the email is processed correctly and doesn’t get placed back into the holding queue, the issue is resolved and the additional steps below are not needed.

If the issue is still present:

1. Download the latest MDaemon installer from here.
   
2. Stop MDaemon.
   
3. In Windows Task Manager select the details tab and ensure that the following processes are no longer running (use ‘End Process’ to stop them if they are):

AVUpdate.exe
AVTray.exe
CFEngine.exe
Clamd.exe
MDaemon.exe
MDSpamD.exe
WorldClient.exe

Rename the \MDaemon\SecurityPlus folder \MDaemon\SecurityPlus_old.

4. Run the MDaemon installer you downloaded in step 2.
   
5. Start MDaemon and allow it to perform an antivirus definition update then process the holding queue.
   
6. If all is well you can safely delete the \MDaemon\SecurityPlus_old folder.

Note: Once a successful update of the antivirus definitions has occurred (this will be initiated automatically as soon as you restart MDaemon following the re-installation of it) the holding queue will be processed by MDaemon. If this doesn’t occur then right click the holding queue in the MDaemon Interface and choose Re-Queue to pass the email back through the antivirus scanner.