I had to update my internet time check to 30 minutes because I couldn’t keep the share visible for very long. The windows troubleshooter suggested I update my time. Unfortunately, checking more often than once per week was a bit tricky to enable. I found this:
http://www.tomshardware.com/forum/55562-45-changing-frequency-internet-time-synchronisation
Read to the end if your shares are not reliably available. I guess my computer’s RTC is different enough from the My Cloud to cause problems.