I've just updated to v47 via FAP, and experienced the same extremely unstable/unresponsive first reboot another user also reported. The 2nd reboot seemed to fix things - everything appears to be working just fine, apart from 1 thing.. my media library is empty and it won't rebuild. I have had a peek in the tracker.cfg even though I've never manipulated it myself previously and it looks fine - my sound/video files are in the watch/index paths.. Help?!