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.

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)

If you’re using Windows Update in installing Windows 10, you can implement the following:

Open the Command Prompt window by pressing Windows Key + X. Select Command Prompt (Admin) from the menu.

Stop the BITS, Cryptographic, MSI Installer and the Windows Update Services. In order to do this, Type or Copy and Paste the following commands one at a time: NOTE: Don’t forget to hit Enter after every command.

net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver

Rename the Catroot2 and SoftwareDistribution In order to do this, Type or Copy and Paste the following commands one at a time: NOTE: Don’t forget to hit Enter after every command.

ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old

Restart the BITS, Cryptographic, MSI Installer and the Windows Update Services. In order to do this, Type or Copy and Paste the following commands one at a time: NOTE: Don’t forget to hit Enter after every command.

net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Type Exit in the Command Prompt then close the Command Prompt window then restart the computer. If that fails, you can try the suggestions listed in this article.