This is very helpful and may explain why every major update for Windows 10 I have to do a reinstall. I suspect it's more than external drives but the problem is any mapped drives will cause a problem. I have multiple nas drives mapped and from what you are describing could be my issue. On the next major Windows 10 upgrade I will unmap all my drives and see if the upgrade will perform properly. It would be interesting to verify this.
Thanks very useful. Cannot understand why Microsoft is taking so long to fix this. One of the reasons why I am contemplating moving to a Linux desktop. They seem to respond to issues more quickly then Microsoft .
Biting the hand that feeds IT
