NVIDIA is reporting that Mac OS X 10.6.7, released a few days ago, removes drivers for high-end NVIDIA Quadro 4000 cards, so machines with these cards will refuse to boot up after installing OS X 10.6.7.

There is an updated driver for OS X 10.6.7 here. The support post is a little vague and doesn't state if the new driver can be installed before updating to 10.6.7 to prevent the issue from occurring, or if it must be installed afterward. If the latter, the article states that you should install a different graphics card in order to boot up to install the new driver, but I'd only advise that if Safe Mode and Target Disk Mode fail.

Update: TUAW is reporting that the NVIDIA support article is inaccurate and that Quadro 4000 machines will boot up just fine but without 3D acceleration and other features. Just install the new driver and these features will be restored.

Does your Compressor settings window have missing items or is completely blank? Here's how to restore the default Apple-supplied settings.

1. Close Compressor if it is open.
2. Navigate to your Applications folder.
3. Ctrl-click on the Compressor application and select Show Package Contents.
4. Navigate to Contents/Resources/English.lproj (or whatever your language is).
5. Cmd-click the following folders to select them: Apple Devices, DVD, Formats, Other Workflows.
6. With all of them selected, ctrl-click on one of them and select Make Alias. Four aliases will be created with filenames like "Apple Devices alias" and "DVD alias".
7. Move the four aliases to ~/Library/Application Support/Compressor.
8. Launch Compressor.

You can add one more item to the ever-expanding list of things that break Final Cut Studio: Bootcamp. Yes, if you have a Bootcamp partition, Final Cut Pro can in some instances hang at startup and refuse to launch.

Luckily the fix is very simple. It seems to be caused by Spotlight indexing and users have confirmed that adding their Bootcamp volume to Spotlight's Privacy list in System Preferences solves the issue for them. Apparently you need several restarts to get the setting to stick but once it does, Final Cut Pro should be able to launch again.

If you did experience this issue, please let Apple know.

Last month I reported that ProKit 6.0.1 was breaking Final Cut Studio (primarily DVD Studio Pro) for some users. Well, it would appear that OS X 10.6.6 automatically installs ProKit 6.0.2* which is causing the issues all over again.

Here are some forum threads on the topic:
LAFCPUG: WARNING: Mac OS 10.6.6 UPDATE (ProKit 6.0.2)
LAFCPUG: I think I installed ProKit 601 by mistake - crashing
Apple Discussions: Prokit 5 v 6 Cant use DVDSP and iLife at the same time

Not everyone will suffer problems with ProKit 6.x but if you're one of the unlucky few, follow these steps to downgrade to ProKit 5.1. Note that this will probably break iLife '11.

It is clear that Apple's engineering team is having difficulty working out what the problem is, so if you are experiencing this issue you should file a bug report (requires free developer registration) and give them as much information as possible.

* For some reason I still have ProKit 5.1 after installing OS X 10.6.6. I don't know why this is but I'm not complaining.

ProKit 6.0.1 has been breaking Final Cut Studio for some people and so far there has been no fix from Apple.

Here is how to restore an older version:

1. You will need to obtain a copy of the old ProKit.framework file either from a friend, another computer on the network or a Time Machine backup.

Update: I have discovered that the version of ProKit 5.1 on Apple's site that is supposedly Leopard-only is also Snow Leopard-compatible. You may need to install ProKit 5.0 first. Before installing, open up the Terminal in /Applications/Utilities and type sudo pkgutil --forget com.apple.pkg.ProAppRuntime, then enter your admin password.

2. In the Finder, navigate to /System/Library/PrivateFrameworks and copy the ProKit.framework file to your desktop.

3. Ctrl-click on the file on the desktop and select Compress "ProKit.Framework".

4. Delete the original file from your desktop and empty the trash. Leave the compressed file there for now.

5. Copy the older ProKit.framework file to /System/Library/PrivateFrameworks, overwriting the newer one. You will most likely need to enter an administrator password to do this.

6. Final Cut Studio applications should now work and it should be safe to delete the compressed file. If they do not, try restarting your computer.

7. If something goes wrong, decompress the compressed file and copy it back to the PrivateFrameworks directory.

(The reason for compressing the file is to ensure that OS X doesn't continue to recognize it as a framework and potentially try to link to it.)

If the installer refuses to install, try using Pacifist to extract the files or try this manual method (be careful).