Windows 8.1 in VirtualBox: Automatic Repair failed

I tried to get a Windows 8.1 system running inside VirtualBox 7.0.12, but it fails as soon as I install the Guest Additions.

All Windows updates have been installed. When installing the Guest Additions, there are 4 errors about Windows preventing the installation of unsigned drivers.

After rebooting, Windows sees something is broken and will do an automatic repair, which yields no results. Rebooting does not help, the system is broken beyond repair :(

Bug report: #21979: Installing Guest Additions in Windows 8.1 leads to non-bootable system

[German] Automatische Reparatur wird vorbereitet [German] Automatische Reparatur

Written by Christian Weiske.

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