A simple solution that worked for me.
I also had these issues with my 10.8.2 iMac
However, safe boot would not work for me, when i rebooted to go into safe mode it would start the progress bar, but stubbornly stop at about 20-25% of the way through.
I left it like this for 2 days, but still it would not progress.
So, to resolve this, i downloaded mountain lion onto a fresh USB stick ( instructions elsewhere ) and then did a full clean install.
I reformatted the primary hard drive.
Did a clean install of mountain lion.
and then did a full time machine restore ( as part of the mountain lion install )
After all that, i was able to safe boot cleanly in normal time, which i did once or twice.
At this point the system is fully recovered, no lsboxd errors, and overall it seems snappier, as it looks like spotlight in particular is working in a cleaner environment.
Prior to this i had done the upgrade ( i.e. not a clean install ) for both lion and subsequently mountain lion.
Hope this helps.
You can modify the /System/Library/Sandbox/Profiles/system.sb file to allow lsboxd and coresymbolicationd to get rid of errors. Make a backup of system.sb first, then add this to end of system.sb file and reboot your system:
;;; MDWorker Fix