After #Windows #Update on dual boot systems: Verifying shim #SBAT data failed: #Security Policy Violation.
Source: https://askubuntu.com/questions/1523438/verifying-shim-sbat-data-failed-security-policy-violation
1) Disable Secure Boot in BIOS
2) Log into your Ubuntu user and open a terminal
3) Delete the SBAT policy with: sudo mokutil --set-sbat-policy delete
4) Reboot your PC and log back into Ubuntu to update the SBAT policy
5) Reboot and then re-enable secure boot in your BIOS.
