Mountain Lion Mail cannot search for non-alpha characters in Subject Lines

Question

Under 10.8.3, Mail 6.3 often cannot successfully find messages if the search string contains a non-alpha character.
I have only tested this searching for Subject lines that are KNOWN to contain non-alpha characters
Specfic examples:
Subject starts with "[ABC..."
Mail cannot find it if you search using "[ABC"
Mail CAN find it if you search using just "ABC"
Subject contains the numeral "2"
Mail cannont find it if you enter "2" as the search string...even if you further constrain the search to "Subject contains: 2"
Other problem characters I have found:
The failure when using square bracket is a real pain since a lot of mailing lists are tagged using strings wrapped in square brackets.
Sometimes it WORKS when I include multiple non-alpha characters in the search string, like "55" or "4/19"
Anyone else see this?

Answer 1

Please follow these directions to delete the Mail "sandbox" folder.
Back up all data.
Triple-click anywhere in the line below on this page to select it:
~/Library/Containers/com.apple.mail
Right-click or control-click the highlighted line and select
Services ▹ Reveal
from the contextual menu.* A Finder window should open with a folder named "com.apple.mail" selected. If it does, move the selected folder — not just its contents — to the Desktop. Leave the Finder window open for now.
Log out and log back in. Launch Mail and test. If the problem is resolved, you may have to recreate some of your Mail settings. You can then delete the folder you moved and close the Finder window. If you still have the problem, quit Mail again and put the folder back where it was, overwriting the one that may have been created in its place. Post your results.
Caution: If you change any of the contents of the sandbox, but leave the folder itself in place, Mail may crash or not launch at all. Deleting the whole sandbox will cause it to be rebuilt automatically.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combinationcommand-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.