I have installed Build 9841 a 2nd time into a clean partition of an SSD. I wiped the previous partition.

It got to 'Getting Devices 95%' quite quickly, but it took well over an hour to get from there to 100%.
I am sure the original install was quicker.

The hardware configuration is exactly the same. I used the same Kingston DataTraveler G4 for both installs.

Google suggest that other people have had similar problems with earlier versions of Windows.

Any suggestions as to what causes this problem?