fix mac mail speed with mountain lion

A slightly technical post today because I have been experiencing some hiccups with Mac mail and Mountain Lion.

It worked fine when I first upgraded to Mountain Lion some time ago, but a two-week ago mini update to Mountain Lion seems to have created a few problems.

I noticed that the mail system wanted to rebuild its database on the iMac and the Macbook Air and I just hit yes.

I should probably come clean that I have multiple email accounts across iCloud, POP, IMAP and Exchange as well the related contacts folders and calendars. Oh and 10s of thousands of emails that I haven't archived. And quite a few smart folders. Let's say its a quite large email environment.

Anyway, that spinning beachball re-appeared - something I hadn't seen for ages. I also noticed that the Address Book was behaving suspiciously and wondered if the two were linked.

I had to go into the kind of problem solving that I'm rather familiar with on my PC, but is rather a novelty to me in the Apple world.

I will cut the long story short.

How I fixed it.

The usual caveat applies to not try this unless you know what you are doing, but simply put, it was a case of rebuilding the Address Book, which has regained the normal speed for everything.

Because I use iCloud and Exchange, all the address entries were stored elsewhere, so I had a safe copy of everything before I started. I quit mail and address book.

I then used the Finder 'Go' command to access the '~/Library' directory (which lets you see the hidden Mac folders).

I navigated to the Application Support folder and deleted the Address Book sub-folder - if you don't use the '~/Library' way to access this area you won't see the folder. A warning from me that deleting this folder will delete all of the address book entries - hence the need to be sure you have them stored somewhere else.

I then restarted Address Book - which had just one entry in it - me.

I then added the iCloud directory back in via Preferences. It took about 10 minutes to repopulate a few thousand entries and to rebuild some lists.

Then same again (in my case) for the Exchange directory. Another 10 minutes.

Restart mail - it was still slow because (presumably) it was rebuilding something.

A hardly ever done reboot (for good measure) and the whole thing was then running back at its proper speed. Fast email, fast address book. Yay.

So I've posted this for anyone else with a similar problem - I had to fix both the iMac and the Air, so I am fairly sure this is a general situation

Dear Apple - I think this needs some attention before the next Mountain Lion update.