Please switch to MC15. You don't need to uninstall MC14.
You can restore an MC14 library in MC15 and also use your MC14 settings (read carefully when you restore).
"Security" programs can cause the kind of problem you've got.
Can't believe I didn't think about that. It was of course my antivirus program (Nod32) that was hindering the update. I deactivted it, and it updated just fine. Well, now I know for next time.
Do you have a link how how to restore MC library and keep previous settings? I believe I tried it, but I didn't get the Recent Albums in same order. But I've probably done something wrong.