I know some of us on this board are scrapbookers (although not me, I can't bring myself to cut a photo)...so I wanted to share a warning with you..
I had to do my son's yearbook page as he is graduating, so I started looking at stuff I had not touched for awhile. To my surprise, 17 folders on my external drive was corrupted, but I knew the data was there, as a mouse point over the folder was giving me a folder size, but I couldn't see the pics.
I took the laptop and tried the drive on another source, same thing. To me, that's a tip off to data corruption rather than a virus. I strongly suspect the drive had a power failure, and in the power down, some of the files got corrupted. Additionally, since I clone as a way of backing up, the corruption got cloned over as well.
I retrieved the data no problem with recovery software, but it took time and what a PITA!
So, in the hopes of preventing someone else from the same pain, look at your photos every now and then. Mine sat unlooked at for quite a while.
I used software called remo recover, as they can recover canon raw files (.cr2) and not every piece of software could do that format. The raw files are the digital negative, and you always want them! It was a $50.00 purchase, but really worth it to me.
I hope this warning helps someone, or prevents someone from a meltdown.
Pat