Since 3years my partner is using Lightroom.
Last year he had done a format C, but because he had recently changed the names of his multiple hard disks, he formatted the wrong one.
He had erased all of our pictures by mistake...
We were able to recover some of them but their are some problems, we can see the pictures in lightroom but then we see some warnings and cant change/access the pictures.
Some pictures have a question mark next to them (warning is: picture missing) and some have an exclamation point behind it (warning is: some problems have occur in lightroom while reading this picture).
I am not at all a lightroom user and even less a computer expert, but since all of my daughters pictures (since she is born) were lost, i hope to be able te retrieve some of them...
When Lightroom imported your pictures it made previews of all of them. That is what you see in lightroom, even though the master images are missing. The previews are of slightly lesser quality than the orginals, but lots better than nothing at all. There is a free program that will let you view and create JPEGs from the preview files. It is called LRViewer and is available here: