well I shun the cloud though sometimes that's hard - MS is very sneaky about it I feel.. tricks me into using it but I get out as soon as I can.
And though we have a home lan I've not copied any Calibre libraries over it. Takes too long. Ours is very slow. Sooner put things on a USB and sneakernet it across and then have the USB backup, too.
I think I'll have to start again. Break it down into bite sized chunks and do some checking. We can check the file size, that's a good clue. And then I could do spot checks across the range to see if they're working okay.
And I will be careful to keep my originals.