Insider 17025 refuses to update to 17074

I appreciate that there are a few similar threads on here, but having trawled through a lot of info, I am still not seeing an answer to my issue.

Ever since Insider Preview 17074.1002 (rs_prerelease_flt), was released on my ring, I have been unable to update to it.  The update starts normally and completes the first part quickly, but the second part stops at a certain point and winds back to 17025.  In settings it tells me that the error code is 0xc1900101.

I must have attempted this update over 20 times and am now pretty frustrated.  Having read other posts, I have opened the 'setupact & setuperr' files, but don't really understand the lines of info.  I have attached them and hope that someone can point me in the right direction.

Incidentally, I have 34GB free on C drive so I dont think storage is an issue.  My C drive is an SSD just for the OS and associated programmes, everything else is on a separate drive.