@brian Looks like you are right about downloading the offline install package. I renamed the original one and this week's WIP installer downloaded a new one OK.
Were there changes to the redist that this week's installer recognized, so that's why it didn't install with the old redist? Or is it set up to just require a new one regardless?
I also noticed that the progress bar on the offline install package downloader shows only about 5-10% when it's nearing completion. I got distracted at the moment of completion so I don't know if it leaped to 100% at the end or not.
Also please note that in the failed attempt with the old redist in place the MS downloads were apparently recognized as being in place because it skipped over each in a second or two, failing only when the language pack downloads started. When there was no redist the MS messages were on the screen longer as if it was actually downloading. Just in case it means something to you.