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 
January 14th, 2010 at 20:08
[...] FIX: Quick look on OSX not working (black box) Jan [...]
January 15th, 2010 at 11:52
Permissions getting corrupted are unfortunately a common problem on HFS+ filesystems. OS X will even refuse to load kernel extensions (drivers) if they’ve got slightly incorrect permissions (0644 instead of 0664 for instance) which can lead to some very confusing problems, especially on hackintoshes.