This problem has started on my linx. A search found this problem occurs on other win 8.1 devices, makes me think its os rather than device. There are a number of sites that offer various solutions, from changing the default time server in setup, to restarting w32time service in registry, to adding a scheduled sync in windows schedule. There are also some freeware apps - atomic clock and Nettiesetup. I am going to give the freeware solutions a go.