When you install the Sophos Outlook Add-in, you may get one of the following errors (depending on the version of either Windows or Office that's installed) and the install will fail:
"Error 1001: unable to access 32bit registry"
"Error 1001: unable to access 64bit registry"
First seen in
Sophos Outlook Add-in
If you were running Outlook 2007 in the past on this Windows system and upgraded to a later version (Outlook 2010 or 2013), there's a bug whereby the installer attempts to associate itself with the older version, which will fail.
What To Do
Prior to rerunning the install, manually create the following registry keys corresponding to the flavour of Windows and Outlook that you're using:
Once the appropriate key has been created, rerun the install.