Poweer outage cauded DVR to not be available until May 2015 firmware update

My mother was watching a recording on the DVR, and local power went out for a few moments and came back on. when she turned the STB and TV back on, she noticed that the dVR was not available. it took a little detective work, but when I allowed the network to apply the May 2015 firmware update, the DVR became available again. What gives?