1803 Boot cycle problem

Win10Home64, Avast user (if that has any relevance). Bought new USB stick 32GB just for this job. It seems to be Fat32 as new. Twice ran through Brink's TUT on this solution. Twice after creating/downloading and during the 'setup' unknown error 0x80042405 - 0xA001A has stopped the process. Is this known, and is there any workaround? Would trying again after a re-format of the USB stick to NTFS be any use? Is it more likely the USB stick I bought is faulty? (It seems to accept file copies & deletes & formatting.)

Thanks for all efforts from the many who are working and reporting on this.
Phil

Thanks for the suggestion. I shall try. Now, how do I start powershell from a blank screen? Meaning no taskbar no nothing. I thought it was white windows key + r or + ctrl/r or similar but have not found it yet.

What method are you using to create the USB flash drive with? I recommend just using the Media Creation Tool provided by Microsoft:
Download Windows 10

Select the "Download tool now" button. Once you run the Media Creation Tool select the option to create installation media for another PC.

Thanks. Keep losing this reply, which is to ask what is the white Windows key combo to get a Powershell?

Full format is the logical next step.