Filing incoming emails in Mailboxes brings my Mac to a halt

Question

I have a problem with Mail since I installed Mountain Lion. If I try to drag my incoming mail into a mailbox to keep it organised, within a few minutes the MacBook Pro slows down to a virtual stop and I have to reboot. Any ideas why? Anyone? Thanks

Answer 1

Step 1
Back up all data.
Triple-click the line below on this page to select it:
~/Library/Caches/com.apple.AddressBookSourceSync
Right-click or control-click the highlighted line and select 
Services ▹ Reveal
from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash.
Log out, log back in, and test. If there's no change, go to the next step.
*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.
Step 2
A. If you use iCloud, uncheck the box marked Contacts in the iCloud preference pane. Press return to confirm, or click  Keep on Mac in the dialog that opens.
B. From the list of groups on the left side of the Contacts window, select All On My Mac. If that group doesn't exist or is empty, skip this step. Otherwise, from the menu bar, select
File ▹ Export ▹ Export vCard
Save the exported contacts to the Desktop.
C. Quit Contacts. Triple-click the text on the line below on this page to select it, then copy it to the Clipboard (command-C):
~/Library/Application Support/AddressBook
In the Finder, select
Go ▹ Go to Folder
from the menu bar, paste into the box that opens (command-V), and press return.
A Finder window will open with a folder selected. Move the selected folder to the Desktop, leaving the window open for now.
D. Launch Contacts. Your contacts will be gone. If you took Step 2, then double-click the file you created in that step and confirm that you want to import from it. Your contacts will reappear.
E. Re-enable Contacts in the iCloud preference pane, if you disabled it. Test. If the issue is resolved, delete the AddressBook folder and the vCard file on the Desktop and close the open folder window.
Otherwise, quit Contacts again and put the AddressBook folder back where it was, overwriting the newer one that will have been created in its place. Post your results.