upgrade to Mountain Lion broke my exchange account

I have exactly the same problem.

Nope. I have the same problem. I've tried the solutions here: https://discussions.apple.com/thread/4136482 to no avail. I cannot get my exchange account to authenticate for mail,calendar, or contacts. My personal email is fine. I upgraded and removed all of the keychain info, my iPhone started asking me for my exchange password as well. My iPad and Outlook on my office PC work just fine. So it doesn't appear to be a problem from our email provider.

Mine is broken, same exact problem. PLEASE HELP FIX IT!!

Same problem here.

It replaces the mail1.xxxxx.com with xxxmail.server.local. I work remotely so it is always the external connection and it seems to not connect.

When I first enter the settings (as they were given to me) the program will pull in the headers, but not the body of the mails, and eventually won't connect at all (by this time the program has changed the preferences to the .local address.

I'm not sure about the technical details, but I think I am having the same issue. Mac Mail only imports new messages, and once they are read they disappear. I cannot see any messages I received before I upgraded OS.

Same problem here. Was working fine before Mountain Lion upgrade.

same issue.

I downloaded the OS 10.8 upgrade yesterday and everything worked fine. Then at around 630pm EST I noticed a software update for OS 10.8, which I installed. Now, my MS Exchange account is not working at all. I've tried removing the account, re-adding the account, verifying all settings, and nothing.

Not surprisingly, my MS Exchange account works fine on iPhone, iPad and through web access.

Apple - Please fix this ASAP! This is causing us to lose time and money. Plus, I have egg on my face from converting my division to Mac despite our IT department's warnings.

Same issue. All my mail is gone including the trash. I have messages waiting but can't open them. Should I just delete this whole update?

Exactly the same issue. Upgraded to Mountain Lion this morning, and following the upgrade I am only able to receive mail using my Exchange (corporate) account. Trying to send mails from my Exchange account results in them getting stuck in the "On My Mac" Outbox. Sending/receiving from my Gmail and iCloud accounts work fine.

Exact same problem. They need to fix this ASAP.

I have very similar problems. Initially, all my Exchange folders were blank including the inbox, and I would only see new messages as they arrived. Later on, after Mail had been running for most of today, several of the mail folders were populated and could be accessed, but the mails seem to come and go. In several instances, all messages of a folder would suddenly disappear after first having been visible and accessible for a while. It seems to be gradually improving, but there is no apparent order to the way that mails appear. Also I noticed that the "wait icon" that normally appears next to folders that are synchronizing is no longer shown. Did Apple change the way that the folders synchronize with the server? I have also tried completely deleted by account on the Mac and reconfigured it.

Apple: Please fix this bug ASAP!!!

I have had exactly the same issue as you describe. Email messages go missing unless you quit Mail and re-start. There's no sense of if Mail is doing anything, the indicators of retrieving messages seem to sporadically work.

This Mail upgrade has been so bad, I'm probably going to have to go Outlook.

Same here, another thing they changed in Mail is that if you drag folders with subfolders into the top shortcut bar, then when you access the subfolders through there, they stay selected and the title of the shortcut changes. A bit annoying I think but that's a matter of taste, I guess.

me, too... when I put in our internal server as "EXCHANGE02" and save the changes, Mail for some reason automatically switches the internal server to "owa.xxxx.com"... but I am INSIDE our network...

Argghhh...