[Spliff]

I had a look at my console and noticed this message:

jnl: flushing fs disk buffer returned 0xd
kernel: disk2s2: device is write locked.
kernel: jnl: do_jnl_io: strategy err 0xd
kernel: jnl: write_journal_header: error writing the journal header!

This can't be good. What the hell caused it and how do I fix it?

[dagaz]

error writing the journal header!

I'm guessing you're using 10.3 and you've got journalling turned on. If it was me I'd boot into single user mode (Apple-S after startup chime) then type "fsck -yf" at the prompt. Keep doing this until it says everything appears OK then type "reboot".

[Spliff]

I figured out the problem. My boot partition had been converted to Read Only by the latest version of MLMac. I repaired permissions which put the boot volume back to Read/Write permission. Then I ran MLMac. Checked the permissions on the volume which were back to Read Only.