More details needed.
What version of MB are you using? (Help > About) INCLUDE THE LETTER (if any) AFTER THE NUMBER
How was MB installed? (Store, Installer, Portable)
How are you syncing? (Wired/USB, MB's Wifi Sync app, other)
Where are you seeing the error? (MB, phone)
If MB, post the error log for the time the error occurs. (Help > Support > Show error log)
If the phone and MB's WiFi Sync app, post the error log.