Q: Could not load Energy Saver preference pane.

Quit System Preferences

Go to your Finder "Go" menu hold the option key to choose "Library"

and delete these files/folders:

/Preferences/com.apple.system preferences .plist

/Preferences/com.apple.screensaver.<12digitHexNumber>.plist

/Preferences/By Host/com.apple.systempreferences.xxx.plist of them)

Also,/Caches/com.apple.systempreferences

What happens when you try in a different account, like your Guest account, or create a new account?

You may be able to repair this with 10.7.4 Combo Update. This is a fuller install, as opposed to an incremental "delta" update so it should overwrite any files that are damaged or missing. It does not matter if you have applied it before.

Scratching head now... try re-install...

Boot up holding command-r keys into Lion Recovery Volume.

The screen should give you these choices...

Restore from TM backup

Reinstall Mac OS X

Get help online

Disk Utility

Choose Reinstall OS X. This will be an install in place and won't affect any of your own data.

Same problem.  There doesn't appear to be a solution anywhere on the net.

It was definetly caused by Mountain Goat.

Found a solution that works for me.

Running Lion 10.7.5 in an MacPro 1.1 - machine is new to me, and is several years old

Deleted the various pref files as per above.

Reinstalled 10.7.5 combo update.

Still could not open energy saver preference pane. Machine was restarting at 10:25pm each night!!!

The solution - I found the system preferences app in the Applications folder

Get Info and selected - Open in 32 bit mode

Given System Information>Software>Preference panes says Energy Saver preference pane is 64 bit, I was sceptical this would work. But it does. At least I can now open my Energy Saving preference pane and get the Mac Pro to behave as I want it to.

Credit to Joseph Delaney in https://discussions.apple.com/thread/4142349?start=0&tstart=0

Tim

I have to say . . . I searched the net for a solution and read many posts before I found this thread. I almost tried various meium to heavy-surgery options above (delete prefs, restart, re-install, scream, etc.). But after reading all the way to the end, I took the easiest, fastest, and seemingly least likely solution. Bingo. Resolved. Thanks!

Same here....I tried all of the other suggested solutions - deleting pref files, reinstalled the bundle, reinstalled the OS......This solution saved me, and should be higher on Google! Thanks!

Thank you Tim!!!!

"The solution - I found the system preferences app in the Applications folder

Get Info and selected - Open in 32 bit mode" -  this worked for me. 

Not only did this solve my OS X 10.7.5 problem and I was able to access the Energy Saver Panel but also this method worked to solve another problem I had: The Apple Mail program would always crash and it said I would need to do a re-install. So I thought, maybe I can set through get info that the Apple Mail program always start in 32 bit mode. I did this and it now works, too. Since my ethernet card burned out on my 2006 Mac Pro, using the app store doesn't work easily so re-installs are an ordeal. But this was a breeze for now (although some performance may be sacrified). THANK YOU TIM!!! and Joseph Delaney.