Equisys technical notes

Technical guidance, explanations and fixes for our products

FIX: Fax Broadcast hangs when sending batch



ID: ZTN1977

This Zetafax technical note applies to:

  • Zetafax 2012 Platform Feature Pack and earlier


When attempting to send a fax to a certain number of recipients (usually more than 300), the Fax Broadcast client hangs just after clicking finish in the New Fax Job wizard.


Depending on the source of the recipients (csv, xls, etc.) the Fax Broadcast client will encounter a condition where it can’t handle more than a certain number of recipients at a time. This is due to a limitation in the Zetafax API when handling large numbers of recipients.


This issue is resolved by adding a registry key that will tell the Fax Broadcast to handle recipients in smaller blocks:

  • Close the Fax Broadcast client if it is open.
  • Go to the following location in the registry: HKEY_CURRENT_USER\Software\Equisys\FaxBroadcast\Options

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Equisys cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved.

  • Create a new String value named ‘BatchBlockSize’ and set the value to 300.
  • Restart the Fax Broadcast client.

Note that if the problem persists you can try to experiment with lower values and test to see if the problem is solved. After this change is applied the Fax Broadcast client may not show the entire list of recipients at first, but as the messages send more recipients will be added to the queue. If you are required to restore the default behaviour of the Fax Broadcast client then the ‘BatchBlockSize’ key should be deleted from the registry.


This has been identified by Equisys as a problem with the software versions given above.

Last updated: 18th December 2013 (WK/MW)

Keywords: Fax Broadcast, recipients, hang

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