MSI has just issued a press release in which they draw attention to the problem. A number of customers have reported back that after installing the Windows 11 update, KB5029351 Preview, they experience a system crash with an error message reporting an "UNSUPPORTED_PROCESSOR" error.
MSI says that they are aware of the problem and are working to find the cause and not least solve it. However, they have not come up with a solution yet, and until they have learned about the problem, MSI's support department recommends that users of an MSI 600/700 series motherboard refrain from installing the Windows 11 update, the KB5029351 Preview update.
If you have already run into the problem, MSI recommends that you try to uninstall the update. However, it may well be a problem to get it removed, due to the system crash problem. However, this can be resolved by installing an earlier BIOS on your motherboard and trying again.
MSI has included in their press release a link to a video guide on how to update or roll back the BIOS versions.