OK, please, following you have an updated one step ahead question regarding my first question post on the title.

The question now is, how possibly get some info or tracing/debug on, which possible reason is leading to this error referring to SYSPREP.

In the net I found several posts for this, and the following link do have quite exact instructions what to look at and try, and I have also been following most of them, except maybe one-two, which I now will still follow on a next Upgrade trial in few hours.

-> https://techjourney.net/windows-10-upgrade-first_boot-failure-with-error-0xc1900101-0x30018/

Here you have a summary of the background info for this case:

• Windows 10 Anniversary Upgrade is stuck at ab. 32% done, in a minute after the second (despite named as FIRST_BOOT) restart at 30%, during the actual final update process phase, with blank grey display and power-on

• after an emergency power-off in a quarter or so, the Upgrade trial will got reversed and following error splash window will pop-up:

   

  We couldn’t install Windows 10

     

  We’ve set your PC back to the way it was just before you started installing Windows 10.

     

  0xC1900101 – 0x30018
   The installation failed in the FIRST_BOOT phase with an error during SYSPREP operation

• the laptop is some 7yrs old with dual-core AMD 1.9GHz 32-bit, memory 3GB, and has been working great with Windows 10 Pro (updated from 8.1) since 9 months

• I know there is outdatings with e.g. display driver, now run with the basic MS one, and Wi-Fi driver etc., but several of the risky devices and also software have been disabled during the Upgrade trials

I hope someone could help me some step ahead on this.

Solution:

I had exactly the same problem, and solved it. In the past I changed my wifi-adapter from Sitecom to Netgear. Now i found out that the Sitecom-software was still running on my computer. If you remove the old wifi-adapter software your problem could be solved. It worked for me. If the above doesn’t work try this:I downloaded the ISO-file from Microsoft, and burned it to a DVD:https://www.microsoft.com/en-us/software-download/windows10(Choose: “Download tool now” and burn the ISO-file on a DVD)Then remove the USB wifi-adapter from your computer, and turn off your antivirus-software temporarily. It is not necessary to remove the software entirely. Restart your computer. Goodluck !  (Greetings from Frank, Amsterdam)