> > Reinstalling the operating system seems to solve the problem. > Almost never you need to reinstall OpenBSD.
There are only 2 parts that could be broken in your case: boot(8) and kernel itself (/bsd). Both could be downloaded from CD or ftp.OpenBSD.org website That is why I told you to try to boot CD kernel using your boot(8) (and vice versa) to check which one is broken and then replace it. But you reinstalled OS, so we will not know it. But my main question is different: Why does this problem happen in the > release 6.2 and later versions? The same process does not cause the problem > in version 6.1. > I do not know.. Unexpected reboot is always some kind of lottery, that is why people use backups and even store /etc/ in vcs and OpenBSD has /altroot where it copies kernel and other files FFS does its best to save filesystem metadata (unless you enable async mount option explicitly, which you did not do I am sure) and fsck (fsck -f ?) almost always helps. It could be that it has nothing to do with OpenBSD version: just an accident
