I had to re-link all images to the source folder, which still sits in the old computer that has become a server now. Is it possible that Capture One doesn't like to work with images from a network?
This for sure can be the root cause of the issue. Are you able to copy some images, or a folder, from your old computer to the new system?
If they can be be accessed fully writable, the network may be the issue. Can you elaborate on your systems and how the network and shared folder is set up? Also, you do use session or catalog? If you use CO8 Express for Sony, it is always a catalog. If you use CO8 Pro for Sony, you use either one.