We have a WD TV Live Plus and randomly it will just restart. Sometimes its while you’re moving files, sometimes its while you are scrolling through… This unit has given us nothing but problems since we first “upgraded” from a WD TV gen 1… When we first got it we had issues with the sound not working, on a very few rare occasions now it still does that. But this restarting business happens almost daily and sometimes more than once a day!
You may try rolling back to an earlier version of the firmware. If the issue persists you may have it replaced.
Having the same issue with the WD TV Live! http://community.wdc.com/t5/WD-TV-Live-General-Discussions/WDTV-reboots-on-its-own-when-scrolling-too-quickly-through/td-p/386213