Spotlight's insistence on re-indexing after every reboot has been driving me nuts for about six weeks. It brought my machine to its knees. Early 2010 MBP, 2.66GHz, 8GB RAM, Seagate Momentus XT 500GB drive running SD28 firmware, OS X Lion 10.7.4, no Boot Camp partition.
I tried the terminal tricks referenced in this and other threads to reset Spotlight's index:
Turn indexing off for /
sudo mdutil -i off /
Clear the metadata store for /
sudo mdutil -E /
Turn indexing back on for /
sudo mdutil -i on /
...No help. (Took its sweet time, too.)
I ran Disk Utility and found some errors on my drive. Rebooted in the Recovery Partition and used Disk Utility there to fix them.
...No help.
Finally I began to suspect that the issue's onset may have coincided with my installation of Sophos' free antivirus utility for the Mac in the days after the Flashback kerfuffle. Now, I'd turned off Sophos' on-access scanning after initially scanning my disk, but given others' warnings about Intego's antivirus utility, I wondered if Sophos might have been contributing to this issue somehow. So I uninstalled it (using the uninstaller app that Sophos provided), and rebooted.
AND IT WORKED.
No re-indexing! No glacial performance affliction for eons after restarting!
It's early yet, so we'll just have to see if subsequent reboots also go well. But this is the first reboot in weeks that hasn't had me gnashing my teeth in frustration.