HelpMaster is available in both 32bit and 64bit versions.

If using Microsoft Outlook, you need to use the same bitness version that Outlook is using.  ie.  If you use the 32 bit version of Oulook, you'll need the 32 bit version of HelpMaster.

You can use a mixture of 32 and 64 installs throughout your business as per individual machine configuration.  Both 32 and 64 bit HelpMaster modules can connect to a 32 or 64 bit SQL Server.

* 64 bit version can only be installed on 64 bit operating systems and requires a 64 bit version of Microsoft Outlook.

Remember, the bitness matching of both HelpMaster and Outlook is per machine only.