After upgrading to Win 10 LR6 worked fine. I did some editing and saved the catalog on exit. Now when I try to execute LR 6 (in Win 10) I get the following error: unexpected error opening catalog." The option to Try Again results in getting the same error, even after shutdown/reboot. Any idea how to get LR6 to execute?
I solved this issue (at least temporarily) by right clicking on Lightroom folder, thence Properties; then Security; then chose Advanced Options and added my username on this PC as having full control of the Lightroom folder. After applying the edit, I was able to execute LR6. This permission issue must be a bug in the early release of Win 10 as I am shown as an administrator but still could not save into the Lightroom folder. Growing pains I guess!