Just noticed that several preference icons in my system preferences window are greyed-out and I cannot open them. The list of greyed-out icons includes security, quicktime, bluetooth, startup disk, and microsoft mouse. How can I get control of these preferences back?

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Does this condition persist through a restart? Does it exist in other user accounts?

The problem persists through repeated restarts, even after a safe boot. I own the only account on the laptop.

Now might not be a bad time to create a second user account; it can come in handy in situations like this, in which it's not immediately evident whether the issue is likely to be systemwide, or caused by some problem in your Home directory such as a corrupt preference file or cache.

In the meantime, with System Preferences not running, you could try moving the file com.apple.systempreferences.plist out of ~/Library/Preferences (where ~/ is shorthand for your Home directory) to the Desktop, then relaunching System Preferences.

You could also try the same thing with the com.apple.preferencepanes.cache file, located in ~/Library/Caches/, but I'd try them one at a time; if moving the cache solves the problem, then you can move the plist back, overwriting the new default plist that'll have been created when you relaunched System Preferences, without needing to reset any preferences. (Note that most of the substantive settings in the various prefpanes aren't maintained in this plist, anyway; it has more to do with which tab was last used in a given pane, where the application window is located on the screen, etc.)

When I moved the cache file on my machine (it weighed in at 4.5 MB), there seemed to be a little bit of delay between my clicking on a prefpane icon and the prefpane opening—expected behavior, given that the purpose of a cache is to speed up access to frequently-used things. (Interestingly, the replacement cache also measured 4.5 MB, so it's apparently not something that starts small and expands over time. Maybe someone else reading this thread can shed some light on the nitty-gritty of how this works.)

> In the meantime, with System Preferences not running, you could try moving the file com.apple.systempreferences.plist out of ~/Library/Preferences (where ~/ is shorthand for your Home directory) to the Desktop, then relaunching System Preferences.

I've always been under the impression that after moving a ~ .plist one must either log out/in or restart; have I been practicing overkill all along, does the necessary procedure vary by .plist, or...?

Thanks.

I think that log out/in or restart is necessary only if the plist is being used by an open program. For example, Finder is always open so moving com.apple.Finder.plist to the desktop won't regenerate a new plist because the old one is still loaded. So, you would have to log out/in although relaunching Finder works just as well. The same goes for the Dock. You can relaunch the Dock via Terminal by typing killall Dock and hitting Return. There may be another way of relaunching Dock but I don't know it.

On the other hand, if you move com.apple.Safari.plist to the desktop while Safari is quit, launching Safari creates a new plist without the necessity to log out/in.

Dkmarsh knows more than I so perhaps he can say if I'm right.

I think the answer is b.

Jon's explanation certainly sounds reasonable to me, but it's possible that there are exceptions to that general rule—for instance, the operating system is always running, so wouldn't that mean that the OS itself would have to be "quit" for a system preference like Sound to be altered by moving its plist? Yet a little experimentation shows that not to be the case. Perhaps whatever process(es) are responsible for managing sound events only run when a sound event is generated.

On the other hand, certain "faceless" applications, daemons, or background processes which are always running under normal circumstances do have to be quit somehow for the state currently maintained in RAM to be altered. SystemUIServer automatically relaunches as soon as you quit it, so how could you drag com.apple.systemuiserver.plist out of ~/Library/Preferences while it's not running?

Turns out you don't have to! Do the plist-moving first, then quit SystemUIServer; it'll relaunch with default prefs. Overwrite the new plist by moving the old one back, then quite SystemUIServer again; it'll relaunch with your customized prefs again.

This means that com.apple.systemuiserver.plist is not written to when SystemUIServer is quit. So maybe Jon's rule of thumb should be amended to "log out/in or restart is necessary only if the plist is being used by an open program which doesn't write preferences currently in RAM back to the controlling plist when it's quit."

I like theory as much as the next guy, but I'm an empiricist when it comes to this stuff: I try it and see what happens.

My theory seems to work fine if it involves third-party apps. I have done this with a few such apps (Opera, PDFpen, OnyX) and it was unnecessary to log out/in. As to Apple apps, your examples are excellent but some apps, like Safari, don't seem to require log out/in because they are not running in the background. I had occasion to do this with Safari and it worked well without either restarting or log out/in.

Did as you suggested. Created a new user, but the greyed-out panels are still greyed-out. Same result when
I moved the two cache files you suggested. Any other suggestions?

are you an Admin user on that account? a Standard user will not have access to several of the System Preferences.