This is also occuring with Ligthroom CC (2015) on a Windows 7 system. Before update (with 5.x) no error occured and I was able to view the MOV files of my Olympus E-M10.
Same here with the MOV, this is really frustrating. Also happens with MP4s that Samsung phone produces. Using Windows 8.1 + Lightroom CC 2015.1 release
I have now seen dozens of these threads indicating that video ceased working in LR. I have NOT seen a fix reported in any of them. My only solution was to install LR4 on another computer and copy my catalog and video files to that computer.
From all the reports I read, the problem seemed to begin with one of the LR 5 versions. I lost video control when I updated from 4.4 to 6 a few months ago. Those original video files work and play fine on ALL other software on that computer (QT, PowerDirector, Davinci Resolve, W Movie Maker and others).