Between the time I asked my question and you responded (thank-you) I read other posts discussing a problem where iPhoto and/or Photo Booth were interfering with Mountain Lion's ability to load Desktop & Screensaver. The suggestion was to remove the iPhoto and Photo Booth libraries from the Pictures folder and place them on the desktop.
I tried this and it seems to have worked - I rebooted a couple of times and each time my desktop loaded fine (not sure why Spotlight would have stalled...but things have improved). Not sure whether the long term solution is in Apple's hands to fix a bug (then be able to relocate iPhoto and Photo Booth back to the Pictures folder or that an action like you suggest is going to be required one way or another. I'm not really looking to spend more time than necessary to get things working (already spent the better part of a day) but I want to fix the problem not just put a band-aid on it.
Do you think resetting the SMC would allow iPhoto and Photo Booth to be relocated back into the Pictures folder and be a permanent solution or is it most likely a programming bug?
Thanks for your time and concern.
I can't imagine what the location of those libraries have to do with your Desktop (other than it holding two more files if you moved them there) and Screensaver. I suspect you could have moved or copied some other files to the Destop and it would have resulted in the same.
If it were a programming bug, many, many more people would complain about the same symptoms here. Looks more like you are an exception.
Resetting the SMC is one of the easy firt things to do if the system behaves strange. The doc I linked to tells you what it does.
Booting into Safe Mode would show if it's caused by any (typically 3rd-party) tools, drivers, apps.
Re-launching the Finder could be another harmless step, but unlikely to fix your problem.
More likely to help is trashing the files com.apple.desktop.plist and com.apple.finder.plist in ~/Library/Preferences.
If it were still persisting, creating and testing a new user account helps telling if it's limited to your present account or a machine/system-wide thing.
Finally, re-installing the system would certainly fix it, latest if you made it a clean install onto a freshly formatted disk. By the way, you do back up, do you?
Your call how far you want to go and how much time you want to devote to it. But be aware that for now you have a fairly flimsy bandaid over it which might fall off pretty soon again. Whatever caused it, and it's unlikely the OS's fault, if you want to fix it you'll need to invest more time, sorry.
Well, I woke up this morning to find the same problems. Your assessment is correct. I have spent the better part of the day running through each of your recommended actions. I got my testing sequence of out of order, so if doing things in the order you had them listed was critical, I may have wasted a lot of time.
I reset the SMC with no change whatsoever.
Re-launched the Finder, nothing.
Trashed the 'plist' items (even added the one for Spotlight since it froze just like Desktop and Screen Saver), nada.
Created a new user account. This was interesting because I thought once I did that and then shut down the computer it would restart by going to the log-in screen and give me a choice between the original and the new user accounts. It never did. Whether I shut down from the original or the new account, the system would always reboot to the original account...but whenever I came into the original account the task bar was missing, etc.; but whenever I came into the new account everything opened and worked right away.
Lastly, I booted into Safe Mode (which is where I currently reside) and everything loaded correctly and speedily. So I guess I am looking at reformatting my disc and reinstalling my system, apps and files...
I do have a fresh bootable clone drive, so I guess what I can do is go to the Start Up Disk app in System Preferences and choose my MacClone, start from it, then go into Disk Utilities and wipe and reformat my current MacBoot drive then rename them both to have each others name and make another clone on the newly reformatted disk. Does that make sense to you? I have never had to do this before...
One concern I have is that my cloned drive will have the same problem(s) my boot drive has - after all it is a clone! I hope I can use it... I also have my Time Machine backup and a third MacBkUp Drive (though that one is primarily for my photography).
In any case, I want to thank you again for your sticking with me and devoting significant time providing guidance. If I don't hear back from you, I will be pursuing the process I described re: swapping drives.
I'll see if I can click on "This solved my question" and "This helped me".
First, if you hold the Option key during boot, you'll be given the choice of which drive you want to boot from - no need for System Prefs.
Next, whatever causes the problem, it's somewhere within your user account. You're right, if you simply clone everything back, however you do it, you're likely to clone the evil source as well. So, "swapping the drives" isn't an option, I'm sure.
Since you seem to have decided for formatting the internal disk and make it a fresh, clean OS X install, you may do so by following one of the many instruction sets on-line: download ML, create a bootable USB drive with the system installer, format the internal disk, then install fresh.
You can use then the Migration Assistent to get your stuff off the Time Machine backup, just try limiting it to data, careful with apps or funky drivers -- those you want to re-install manually, and make sure that it's the newest, 100% ML-compatible versions. Hands off anything else.
To be safe, you may as well move your data only manually from either of your backups. Anything "manual" will cost you more time, but unless the cause of the trouble is known it is the safest way to re-build a stable, lean system.
If you are desperate for saving some time, you may as well build a new user account on the present OS X, again by manually moving your stuff to that new account, at some point eventually deleting the old account.
Just be alert that, if it wasn't yourself, there is something sleeping on your disk that has caused the trouble, and you don't want to wake it up again. Compare the Login Items of both user accounts, there might be a hint towards the cause: if something loads in the old account but not in the new one, it could be the cause. "Could" be...