Hi, just a note of appreciation (to my surprise!) to MS- When I finally tried upgrading to 1709, I immediately got that error number, together with a link to contact MS support.

I thought I'd try it rather than do the research (yes, really lazy).

Anyway, the agent cleared the Software Distribution\Download, temp and Prefetch folders (I had run Ccleaner beforehand) - and the installation proceeded successfully.

So far no great problems- 2 broken security programs- one needed reinstalling, one now has a licensing problem, and one utility program needed 'Repair' via its installer.

One difficulty- settings for delaying updates used in 1703 were confusing Windows updates in 1709. That needed a registry mod as I couldn't resolve it in group policy in 1709, although I'd used group policy to set the delay in 1703.

Initially 'Pause Updates' in Settings was greyed out until I found the right things in the registry.

That leaves the same problem I had after upgrading from 1607 to 1703- Advanced startup options don't work. Apparently MS has changed its drive numbering system from 1607 to 1703, starting at 0 rather than 1.
Whether that's indeed related to this problem is unclear, as it's unusual. Anyway, I'll fix that with a fudge tomorrow.

A couple of tweaks and 1709 looks as I've had Windows from Win 8:
Click image for larger version. 

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