On October 23, just over a week ago I wrote that my 1709 upgrades to Windows 10 had gone mostly trouble-free. Alas, I was gilding the lily where one of my 1703 upgrades was concerned. At the time I wrote the post, the machine was in its final reboot phase just before handing off control to the new OS. That phase took about a week to complete successfully, as it turns out, and involved considerable research and what-if repair attempts to resolve. Everything I tried failed, until I discovered the cause almost by accident. As it turns out, bad RAM nixes 1709 upgrade completion. It also throws different errors on multiple failures, which makes diagnosis difficult.
When Bad RAM Nixes 1709 Upgrade, Then What?
On Monday, 10/30, I ran the hardware diagnostics from Lenovo Companion on the problem laptop. A Lenovo X220 Tablet, it has been (mostly) a rock-solid, trouble-free machine. The “Quick Random Pattern Test” for memory failed on that PC as soon as the test started. Reasoning that one of the SO-DIMMs might have failed, I popped the first one that came to hand (a Patriot 8 GB PC3-12800 module) and tried again. As luck would have it, the memory test went on to complete successfully using the sole remaining 8 GB module.
Alas, this is not what I saw from Lenovo Companion until after removing the failed/failing RAM module. I got the red X of failure instead.
Guessing that memory problems during the install could have caused my strange symptoms, I ran the Windows 10 Update Assistant one more time. And indeed, this time the OS installed successfully. My best guess is that the Windows Installer only attempted to access memory addresses above the 8192 GB high watermark for the first SO-DIMM during the final phase of installation. And it was only when the system tried to use the second SO-DIMM that things got wonky. Now that I’ve removed the apparently failing module, all is working properly on that PC. I’ve ordered a replacement from Newegg ($62.99 + $0.99 shipping) and will return to 16 GB operation as soon as it shows up at my front door. Case closed!