I frequently have my apple mail program "crash" by giving me the endless spinning rainbow wheel. It begins when I try to compose a message and just type the first letter of the intended recipient in the "to" box, leading to the crash and requiring ctrl-alt-esc to get out. This is despite multiple reboots and even a reinstallation of 10.8.4. Ideas?
Right-click or control-click the highlighted line and select
Services ▹ Reveal
from the contextual menu.* A folder should open with an item selected. Quit the application if it's running. Move the selected item to the Desktop, leaving the window open. Relaunch the application and test. If there's no change, quit again and put the item you moved back where it was, overwriting the one that may have been created in its place. Otherwise, delete the item you moved.
*If you don't see the contextual menu item, copy the selected text to the Clipboard (command-C). 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.