Hi Mrdbeta,
Thank you very much for your prompt reply.
I tried your method step by step (as I can understand, to completely remove the Windows Update folders and force Windows Update to re-download), but unfortunately, it didn't work. Same error message.
I can't uninstall KB4579311, because I couldn't install it - if I could, no need to ask this question here.
I checked the Windows Update History, there is no KB4577266. This is a new laptop that I purchased last month. Here is the updates in the history page: