If you have an iPod, iPod nano, or iPod classic, you may be unable to sync contacts or calendars with Outlook 2010 64-bit version.
The following dialog may appear on your computer:
"The 64-bit version of Outlook is not supported with this iPod."
"There is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client."
There is no option to "Sync to Microsoft Outlook" in the Contacts and Calendars preferences panel in iTunes. iTunes might also display the message "Microsoft Outlook must be installed in order to synchronize contacts/calendars."