The files that won't open are 2009-2012.
Yes I have similar files from that time period that do indeed open normally, more files that open than don't open.
These files were moved from my previous MacMini to my current MacMini in June 2014. I used Migration Assistant to move files from old to new Mini. I am pretty sure that I opened them since but am not positive.
I don't use Time Machine but I do have a external HD that I use as a backup. I close my system about every 2 months and the files on the external HD will not open either and I have tried to open them by copying them to my internal HD and also booting into the external. Won't open.
