I’ve recently replaced the hard drive in my MacBook Pro with a higher capacity one (write up to follow). After restoring from time machine I found that quick look no longer works. If you try to quick look a file (select file, press space bar) you just get a black box. If however you select two files, hit the space bar, then click on the index sheet button (little button with 4 windows in a 2×2 stack), quick look seems to work – but only in the index sheet.
This is a common problem, but took some forum trauling to find a solution, so i’ll save you the work.
Simply reinstall the Mac OS X v10.6.2. Update. I was running 10.6.2 already, and it simply reinstalled over the top.
If this doesn’t fix the problem, boot your MacBook from the install DVD, select Utilities > Disk Utility, and “Repair Disk Permissions” – you’ll have to boot from the install media if you are repairing the same drive that your system boots from.
Good luck – post a comment and let me know if this works for you. You could always talk to me on twitter too