From the NAPP Help Desk
The National Association of Photoshop Professionals (NAPP) offers e-mail assistance to its members. Here is some advice from the NAPP Help Desk related to issues in this chapter.
Transparency and Background Layers
No matter how I set the transparency grid, I can't see it. What's wrong?
Open the Layers palette and look for a layer named Background. A background layer does not support transparency, so you won't see the grid "behind" it. To correct the problem, convert the background layer to a regular layer by renaming it. Click on the word Background in the Layers palette and type the new name.
I set up all my palettes, tools, and settings just the way I wanted them and then immediately quit Photoshop. When I restarted the program, my custom settings weren't there, just the defaults. Any ideas?
Check the Prefs file to see if it's locked. Photoshop won't warn you when it can't update the Prefs, assuming that you've locked the file to protect it.