Microsoft is advising its customers to install the 32-bit, rather than the 64-bit, version of Office 2010 "We strongly recommend most users install 32-bit version of Office 2010 on both 32 and 64-bit operating systems because currently many common add-ins for Office willn't function in the 64-bit edition," Microsoft warns. "There may be technical issues with the 64-bit version and in order to install a 64-bit version of Office 2010 product users must have a 64-bit supported operating system on their PC," Microsoft adds. Even some of Microsoft's own Office plugins are not yet compatible with the 64-bit software, including the Outlook Social Connector, which hooks software into social networks such as Facebook. Third party plugins from LinkedIn and Symantec are also 32-bit only. The advice is tucked away in an FAQ about the Office 2010 Tech Guarantee programme, which will ensure that buyers of Office 2007 will get a free upgrade to the new Office suite when its launched.