Paul, that was interesting ... my original /Containers/com.apple.mail folder turned out to be 56MB and when Mail recreated it on launch, it was only 1 MB (although the contents are the same, various links to my almost all my other folders.)
But sadly, this didnt work for me - once Mail recreated the above two folders, despite this size difference, Mail's behaviour had not improved at all.
I was having issues with Mail after Mountain Lion "upgrade" that caused the preview pane, after clicking on a email to show up about 20-30 seconds later. You wouldn't have the ability to reply or delete for another 10 seconds or so.
I tried pretty much all of the solutions above including repairing permission, deleting and adding back contacts, etc....
I called support and here is the solution, after more than an hour on the phone with them. Not sure which one did the trick, but they are easy enough to try -
1) Shut down, unplug 15 seconds, plug back in, wait 5 seconds, restart
see if that helped, then if not,
2) Shut down, power back on as you hold down CMD+Opt+R+P. You'll hear the typical chimes as it's restarting. Continue holding those four keys until you hear the second chime and then you can let go.
Mail is back to working as it did before Mountain Lion for me. Hope that helped.
I have tried everything listed in this 4 page discussion and I am still sitting with a non-working Mail. I am at my wits end .... is there anything else besides throwing the damned MBP out the window?
I've been using Mac for 3 years now and this is the first time I have been ready to quit and run away. ML was the WORST thing I ever did ... I have now been sitting at work for nearly 6 hours without mail and I cannot do my job without it.
I will take any advice gladly ... PLEASE???
I finally solved this problem for me by disabling all the Mail plugins - which immediately resored Mail to its zippy performance - and then enabling them one by one to discover the culprit. In my case, I discovered MailTags to be the cause of the problem. Developers Indev have acknowledged the problem and are working on a fix.
You may not have MailTags, but if you have ANY plugins I strongly suggest you try disable them.
To disalbe plugins, you need to quit Mail, go the /users/[yourname]/Library/Mail/Bundles folder and move them to any other folder (there may even be one there called Disabled) then restart Mail. Each time you move something in or out the bundle folder you must quit Mail, do the move, then restart Mail.
(To get to the Library folder, click on Alt while opening the Go menu in Finder. You'' see Library appear in list - just click on it.)
I know it doesnt solve everyone's slow Mail, but it worked for me after I tried everything. Good luck!
Hi there, thank you for this response. I don't have any mail plugins at all. Never got that far .... this is driving me nuts as without my email I am totally blind to what is happening ... Even if I manage to get it up and started, it just sits there like limp spaghetti and does nothing ... except for gobble memory and CPU - both of which are completely ridiculous.
Any other possible suggestions???
The other basic option is the repair permissions route, but this is the extended one which can really make a difference for some people:
1. Restart the computer, holding down Alt until the start up options appear - choose Restore 10.8 when they appear.
2. Once the restore system has loaded, choose Disk Utility. Run Verify Disk and Verify Permissions - if anything needs fixing, you'll get instructions.
3. Once thats done, quit Disk Utility (but not restarting or shutting down) and from the Startup Options menu still on the screen, or from the Tools menu on the menu bar, choose Terminal.
4. A terminal window will open with a command prompt (your username and some other stiff.) At this prompt in that window, type resetpassword (as one word like that)
5. A new window with options appears. Select your user account from the drop down list, and then click the 'Reset Home Folders Permissions' button at the bottom. Note: your password and everything else is safe, nothing will be reset except some critical permissions.
6. It can take a few minutes or very much longer. Go make tea if necessar. There is no feedback - dont panic. Wait until the button says Done or something similar.
7. Now restart the Mac and try Mail again. Worked for some and not easy to find so I repeated it here.
Success is mine - however, what a mess to get there!!! I finally managed to disable each and every mail address I use to see if I could track down which one was causing the problems. I also disabled address and calendar so that they were not working either. I was still getting the same issues. I finally figured out that if you have unread mail in an imported mailbox - which I had 1000's of, mail just did not do anything but try and check these unread mails. Once I deleted my imported mail, everything worked like a charm. So basically, I have to start from scratch and import my messages a few 100 at a time and them make sure they are all marked as read. BUT - I also believe that all the other fixes I tried (those above) were part of the solution ... there is definitely some kind of a bug in Mail with the address issue!!
Thanks very much to you for your assistance!! Now I am off to get something MUCH stronger than tea!!
I did the way dsjr2006 posted, and... yepppy.. no more stupid spinning circle, and force quiting.
The only things different I did was after I unticked everything under icloud, i also logged out of it.
Once I booted back up, I opened mail, put in my email address details, bang! straight away it worked, then i went into icloud, re logged in, and it re sinked with my contacts on my iphone, and now it works perfect No more late nights trying to figure out what the **** went wrong!
just wanted to say thanks! I don't know if I should wait a little but for now it looks like the fix you suggested worked for me. I did a clean install of ML but I restored my home directory etc from TimeMachine. Deleting the AddressBook directory and switching the contacts off and on in iCloud's settings seems to work.