Messages stuck or growing in the \mxscan hold 1 folder

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Mxscan works by first moving the messages to a temporary holding folder under C:\Program Files\Mail Enable\Queues\SMTP\Inbound\Messages\mxscan_hold_1. The messages are then processed by the MxScanEngine and put through an array of Spam, Virus and other filters. Messages are then moved back to the C:\Program Files\Mail Enable\Queues\SMTP\Inbound folder for normal delivery by MailEnable.

In situations where you find that then number of messages in the C:\Program Files\Mail Enable\Queues\SMTP\Inbound\Messages\mxscan_hold_1 is growing or that the MxscanEngine is not moving the messages back to the Inbound folder the following are some of the things that you should look at

  1. The first thing you should check is your mxscan-service_XXXXXX.log file. Run through the log file to check for any obvious errors or issues. You can also do a find for "Error in [" text when viewing your log file
  2. As a general rule of thumb you should set the MxScan Concurrent Thread count (Settings->Global system settings) to 1 thread for every 5k of daily average message volume (Applies to the Pro version only)
  3. While reviewing your log file you can manually trace a particular MessageID and follow through the timestamp to see which of the tests are taking the longest amount of time. After determining the backlog you can then choose to optimize or disable the particular test
  4. A lot of the spam filters utilize DNS servers for lookups. As such please ensure that the DNS servers you have set in MxScan respond to recursive requests. Preferably a local DNS server should be used instead of a general ISP DNS server for quicker lookups.
  5. The win32 SpamD that is included with MxScan is single threaded and at times can be a bottleneck especially when you process a lot of messages. One recommendation is to consider replacing the SpamAssassin filter with Message Sniffer. Message Sniffer is multi-threaded and is extremely fast and accurate at catching spam messages
  6. Set your AntiVirus/AntiSpam filter mode to INCOMING only instead of INCOMINNG & OUTGOING
  7. For servers where the daily messaage volume constantly exceed 25k messages a day and with a high spam ratio please take a look at and consider following some of the suggestions provided.
  8. If you have any other ResidentAV running on the server please exclude the C:\Program Files\Mail Enable\Queues\SMTP\Inbound (including subfolders) and the C:\Program Files\MxUptime\MxScanME (including subfolders) from the residentAV
  9. If you see a lot of IO exception errors in your mxscan log file and have a heavy message traffic volume then its possible that there are Disk IO issues. This means that your servers harddisk cannot keep us with the amount is IO required.
  10. Please ensure that you are only running one MailEnable MTA Event filter. It is not recommended to run MxScan at the same time with other 3rd party MTA Event filters.

If the above suggestions/tips do not help to resolve your issue, then please open a ticket with us via the customer portal login at and included a zipped copy of your current day MxScan.*log files. You will also most likely need to provide us with temporary Remote Desktop login details so that we can assist you in resolving this issue in the shortest time possible.