Q: Every time I open Desktop & Screen Saver in System Preferences, I get the error message: "There was a problem connecting to the server 'idisk.mac.com'. Contact your system administrator for more information." The message will not go away when I click OK.

try deleting the  screensaver.plist.

Finder>Go>Go to Folder

copy and paste:

~/Library/Preferences/com.apple.screensaver.plist.

restart you rmac

iDisk might be an image source in your left-hand pane; if it is, remove it and re-add it.

Quit System Preferences, and also quit iPhoto if it's running. In the Finder, temporarily move the iPhoto library (usually located in the Pictures folder) to the Desktop. Open the Desktop & Screen Saver preference pane again. If you don't get the error message, something in the iPhoto library is causing it. Follow the procedure on the page linked below to repair the database, and if that doesn't work, to rebuild it:

Rebuilding the iPhoto library

If you still have the problem after doing that, use the procedure on the page linked below to find and remove the invalid items:

Connection Failed, Server Does Not Exist

I finally solved this today, and like Brimstin have had this problem for many months. Whenever I opened the Desktop/ScreenSaver prefs, I would get the idisk.mac.com error, in my case four times in a row.

None of Linc's suggestions worked for me, as good as they were (I know they worked for some other people). I did use his tip of moving the iPhoto Library aside to narrow the problem to that. What I tried included:

- deleting all ~/Library/Preferences that referenced desktop, screensaver, or iDisk

- repairing the iPhoto Library database

- rebuilding the iPhoto Library database

- searching for aliases in my iPhoto Library (there were none)

- selecting all photos and correcting the ones that had bad links (nothing I corrected would stick though)

What finally worked was when I did a search of my whole iPhoto Library like this:

    grep -R idisk ~/Pictures/iPhoto\ Library

and it showed me (apart from a couple of Library.apdb references) four problematic files—the same number of errors I was getting in System Prefs.

The problem files appeared like:

     Binary file /Users/USERNAME/Pictures/iPhoto Library/Database/Versions/2010/06/04/20100604-144233/5Vt4pO7xQASBHKmXUjRA3h/Master.apmaster

These are reference files:

     $ file Master.apmaster

     Master.apmaster: Apple binary property list

So I looked inside them:

     $ less Master.apmaster

(cat also works, unformatted, but for some reason plutil does not decode the fileAliasData).

There I saw the smoking guns — in part:

     /Shared/Documents/Images/some_picture.jpg

     /Volumes/IDISKUSERNAME

     http://idisk.mac.com/IDISKUSERNAME/

Apparently I had put something from my mounted iDisk into my iPhoto Library.

I opened iPhoto, found these files, deleted them, and my problems went away. Hope this helps!

As a side note, particularly for those readers that are as not tech-savvy, all of these files were flagged when I did Linc's trick of selecting all photos, starting to move them, and getting the "original file not found" error. If you don't care about keeping all these files with lost originals, you can identify them this way more easily.

That didn't work for me because I couldn't tell which of the 10 files flagged were the 4 iDisk ones and didn't want to delete all of them. Also, I tried reconnecting which should have worked including for the iDisk ones, but for some reason they wouldn't relink to the local versions of the files I found.

Wow, that's a quality follow-up.

Thanks! The grep helped me to pinpoint the elusive broken links and repair them. It should be noted that a problematic iPhoto library affects more than just iPhoto. I couldn't open iMovie without getting these error messages nor could I even change my system user photo. Now I can try to regain previous levels of sanity :-)