Share your experience!
This is what I would do
Repair the phone with PCC > uninstall any antivirus app > do NOT download/install any new app > use the phone like that, without new apps, for 6 hours or so, check if you encounter the same issue, if you don't then it's a third party app creating this problems.
Bridge (for Mac)
Alternatives on How to backup Xperias
http://talk.sonymobile.com/thread/36355