Sony Xperia connection problems
After much searching and head bashing, I finally got my Xperia to connect via USB.
Beyond doing all the normal stuff: rebooting the device, installing Sony’s PC Companion to get the latest drivers, still nothing worked. PC Companion would detect when the device was attached but wouldn’t connect.
This little tid-bit is the key, I had to flush the cache for their “MTP extension service”
Go to:
Settings > Apps > All > MTP extension service > Clear data/cache
also stop the extension.