I don't have an answer per say but had something similar happen to me like that. Mine started around the same time frame as yours did. One day I had backup dates the next nothing, all dates where gone. So for almost two months went by trying to fix this problem but no go. So something clicked and I checked with MS update center and sure enough there were some updates that fit the slot when the problem happened. I couldn't pin it down to what exact update and what date it happened. Then I checked the backup dates again and lo and behold they where all there and working. I couldn't figure that one out at all. Then checked MS update center again and again there where updates the fit the slot and time frame of self correction. Still I not sure what happened. Is this a coincidence or not, who knows, it's MS at it best. Like I said I don't have a fix for your problem just and answer as to what happened in my case. I have two hard drives in my system and backup my system daily to that hard drive. Yours being a partition, I'm not sure if the same general guess applies to your situation as mine. I would recommend an external hard drive and backup to it. The only answer I can give you is to save what data you want and reformat, I know it's not what you want to here. I clean fresh system and a external hard drive is a nice way to restart, like new. Check to see if any MS updates corresponded to time frame of your problem. I know that some MS updates can and do cause issues with some systems. Why, who knows, it's MS. Good luck and let us know what you decided and what the results were.