Please take each of the following steps that you haven't already tried. Back up all data before making any changes.
Step 1
Boot in safe mode.
Log in and see whether you still have the problem. If you don't, it's caused by one of your login items or a system modification that loads at startup or login. Ask if you need help identifying it. A common offender is "Adobe Synchronizer," which is a component of some Adobe products.
Step 2
Triple-click the line below to select it, then copy the text to the Clipboard (command-C):
~/Library/PDF Services
In the Finder, select
Go ▹ Go to Folder...
from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return. A folder may open. If it does, move the contents to the Desktop, or to a new folder on the Desktop. Log out and log back in. Test. If there's no change, put the items you moved back where they were and continue.
Step 3
Open the folder
~/Library/Preferences
as in Step 2 and move the following items in that folder to the Trash, if they exist:
- com.apple.recentitems.plist
- loginwindow.plist
Log out and back in again, and test.
Step 4
Other possible causes are references in the iPhoto, iTunes, or iMovie library pointing to the server, and bookmarks in the Preview application.
