Recently when syncing via Bluetooth, using Sony SyncStation application
I would receive a 'failed' message on my phone. Phone and PC had been
syncing just fine in the past.

The desktop and phone would make a Bluetooth connection, it would
attempt to sync but failed.

I found a post from a few years back that recommended to check Internet
Explorer for 'Default Email Client' (programs tab in IE). My setting
to use Microsoft Outlook for this was not present.

I re-setup Outlook as the IE email client and syncing is now working.

Bob H

* Sony Ericsson Sync Station Program for synchronising your Microsoft
Outlook™ calendar and contacts with your phone

See More: K700i Outlook Sync Problem - Solution