MySQL: Can't open privilege tables: Incorrect information in file: './mysql/host.frm'

[benjamin.choi]

I cannot start mysqld. When I do /etc/init.d/mysqld start, it fails with a timeout error.

When I took a look at /var/log/mysqld.log, I saw

050625 21:06:10 mysqld started
050625 21:06:10 InnoDB: Started; log sequence number 0 43634
050625 21:06:10 [ERROR] /usr/libexec/mysqld: Incorrect information in file: './mysql/host.frm'
050625 21:06:10 [ERROR] Fatal error: Can't open privilege tables: Incorrect information in file: './mysql/host.frm'
050625 21:06:10 mysqld ended

This happened with MySQL 3.23, and persisted even after I upgraded to MySQL 4.1.

[benjamin.choi]

Fixed by copying host.frm from another machine with FC4 installed.