„Windows failed to start. A recent hardware or software change might be the cause…“

I want to move my Bootcamp partition from the internal SSD of a MacPro 7.1 to an external SATA SSD connected via USB. I created an image of the working Windows installation and restored it to the external SSD. Bothe volumes have different sizes (internal Bootcamp partition 500GB, external SSD 1TB).

When I try to boot from the external SSD (shown as „EFI Boot“) I get the error message „Windows failed to start. A recent hardware or software change might be the cause…“.

Any advice how to solve?