Similar problem here, on two different laptops. I discovered that earlier versions of the client were still showing up in my list of apps, so I uninstalled them, and uninstalled the new version on each, then re-installed the new version from scratch. It found the cameras and NVR on the local network OK, but I had to input each of their passwords. So far, so good.

On 8.12.1 we get no images even though the client says that it is connecting to the cameras.
We didn't get any warnings about missing directx files, but from what others are posting here, I guess that is the problem.
Fortunately I found 8.8.5 on an old website page, downloaded it, reinstalled, and now everything is working fine again.
Obviously it would be good to have the latest version - but we do need it to work for us!