I've encountered strange issue with LR. All my photos are securely stored on NAS drive and in LR I just have smart previews. However, LR started to toggle whole folder tree between available / unavailable states so that I can't work on photos comfortably anymore.
Just to exclude some obvious answers:
This issue was annoying, now looks like show stopper as it happens all the time...
Any guesses? What should I check first?