CoreStorageGroup::completeIORequest - error 0xe00002ca

I've just had a couple of frustrating days tackling some annoying symptoms so I thought I'd provide a fix here for anyone else Googling the same error messages.

I'm on OS X Lion 10.7.2, using Filevault 2 on a 2011 17" Macbook Pro (8GB RAM with the stock 750GB Toshiba MK7559GSXF drive).

I upgraded from Snow Leopard to Lion on my old 15" 2008 MBP and then recently migrated to the 2011 MBP using Time Machine (i.e. there was several years worth of junk lying around pre-Lion and pre-2011 MBP). OS X is up to date, even the new EFI update this week.

The symptoms were:

1) Beachball every few minutes - all applications would stop and hang for between 10 and 20 seconds. Some applications seemed more prone to triggering the problem but I think it was coincidence. The mouse cursor moved but everything else stopped.

2) The following errors appeared in the kernel log and console after the beachball event:

kernel: CoreStorageGroup::completeIORequest - error 0xe00002ca detected for LVG "Macintosh HD" (EE74B25C-0D2C-49B5-BF7D-EFF4D0D4EA18), pv F035EDD4-32D0-4718-B83B-2D61C774E567, near LV byte offset = 320161787904.

kernel: disk1: I/O error.

Note that the CoreStorageGroup error contains a drive label, after a while I realised that my disk wasn't even called 'Macintosh HD' so an unknown application was trying to access an unknown file on a drive that didn't exist. I checked my drive ID using Macpilot and it wasn't the same as the one in the error (EE74B25C etc).

3) There were no other error messages around these messages that pointed to a specific application.

4) All disk checks reported no problems at all. Disk Utility (both from within my user account and from the Lion install disk) and fsck from single user mode were happy.

I was bracing myself for a reinstall but then I worked through some tidying up and one of these fixed the problem:

1) Went through ~/Library/Preferences and deleted some files and folders with corrupt names. I also deleted some old .plist files while I was there.

2) I thought Spotlight might be a problem (maybe an old index entry expects to see a file on 'Macintosh HD' when my drive is really called something else) so I ran 'sudo mdutil -E /' to erase and rebuild the Spotlight index from scratch. That took about 45 minutes.

3) Zapped the PRAM (Command-Option-P-R quickly after power-on).

4) Found a corrupt .m4b audiobook in my iTunes library. I stumbled across this really, I noticed that the errors were more frequent when I was listening to the audiobook. It was corrupt in some way because Finder couldn't work out what kind of file it was. I thought this might also cause problems with Spotlight so I deleted the corrupt .m4b file.

5) Used Macpilot to clear Recent Files List, Clear User Cache, rebuild Launch Services, rebuild Help Viewer Database and run the daily/weekly/monthly cron jobs.

I'm annoyed that I can't tell you which of these actually solved the problem. I'm 90% certain it was a combination of deleting the corrupt .m4b file and recreating the Spotlight index. The .plist files and PRAM zapping might have just made me feel better.

I hope this helps someone. If it does, just reply to this thread please with the actual solution :-)

Regards.