The Windows client for Lime CRM is a 32-bit application that can only communicate with other 32 bit applications. If you use Lime CRM with the 64-bit edition of Microsoft Office some components of the Lime CRM Office integration will therefore not fully work.
Microsoft's recommendation has until very recently been to always install the 32-bit edition of Office unless there are very specific reasons for using the 64-bit edition. Microsoft has now changed their recommendation, however at Lime we still recommend our customers to install the 32-bit edition of Office for full compatibility with Lime CRM (see our system requirements).
Lime has launched a number of development efforts to replace the existing Office integration with new functionality that works independent of platform. An example of this is the new email add-on that works just as well on a mobile device as on your PC.