Office 2010

[armsys]

The current version of UR4.1c won't be compatible with Office 2010 x64. All UR sync with Outlook will be lost.

[kinook]

Unless you need > 2GB Excel files, it's best to use the 32-bit edition for better compatibility.
http://technet.microsoft.com/en-us/library/ee681792%28office.14%29.aspx