Why can't you develop the photos? What happens when you try? Is there an error message? If so, please quote the exact complete unedited word-for-word verbatim error message.
I don't have an error message.
When i go to 'develop' I can edit a picture (picture X), but the moment i go to another picture (picture Y), the first picture (X) is restored to default. Changes are gone.
I can't do a backup of the catalog as well...
I gues it has to do with read only....
but i tried to run as administrator, but it stays the same...
i recently installed windows 10 and have a new graphic card (nvidia geforce).
Try to disable the GPU under Edit > Preferences > Performance.