Exchange 2K3, Outlook 2K3. Out of the blue - "Unable to open your default email folders. You must connect to your Microsoft Exchange server computer with the current profile.......

Have you checked this:

http://support.microsoft.com/?kbid=156304

Unfortunately that doesn't appear to be related to my issue...

If it is one user and follows the user to another machine, then the account has a problem. I would be looking to recreate the account and then attach the mailbox to it.

Simon.

I'd rather not have to remove his account if not absolutely necessary. Also, it doesn't appear as if it's posisble to remove the account without also remove the mailbox. I just created a test account, logged into a machine as it, setup the email and it works. Logged off the machine with the test account, then removed that account from the AD, and it "asks" me if I also want to remove the mailbox associated with the account and there's a checkbox next to this option. It is checked by defualt and you cannot uncheck it (seems kind of silly to me). So you are FORCED to remove the mailbox when remove the account from the AD.
So I did that with this test account to verify something I figured woud happen. When I then recreated another test account with the same name, it told me that a folder existed all ready and that I would have to verify that this account had permissions to it. Also, it of course creates a new SID or whatever so when I logged back onto the test machine as this new test user of the same name (recreating the situation that would/will arise if I recreatethe account of the actual user that is having this problem).. it logs in but creates a new profile, so anything that the real user has in his profile on his computer (My Documents and so forth) will not be there for him.

That would create more headaches that I'd rather not deal with if not absolutely necessary. I am looking for a solution to the problem, not a runaround.

I appreciate the suggestions so far, but I really do want to get the actual problem figured out.

Increasing point value.... really want to get this taken care of.

If you drop the account, the mailbox becomes disconnected. It is not deleted automatically. You then create a new account without making it mail enabled.
In ESM in the mailbox list, right click and choose Run Cleanup Wizard. The mailbox will have a red cross over it because it is orphaned. Right click on the mailbox and choose Reconnect and select the new account that you have just created.

If recreating the account put the data at risk I wouldn't have suggested it.

Simon.

Again, I appreciate the response, but I am looking for a solution to the actual problem. I really would like to find out what is wrong and get it fixed. I won't learn anything by deleting and re-creating an account.

I doubt whether you will find the problem.
Single user issues are not really worth the hassle of spending hours looking for an issue unless you know what it is. If you have the time to burn, then do it. I and my clients do not have the time - I work on the fastest fix, which is often recreating accounts, profiles etc.

Simon.

I think the Offline Storage File (OST) may have become corrupted. Try to recreate the OST for the users Outlook profile.

1. Go to C:\Documents and Settings\%user%\Local Settings\Application Data\Microsoft\Outlook.
2. Rename outlook.ost to outlook.ost.old
3. Relaunch MS Outlook

This should recreate the default outlook.ost file, and resync this new OST file with his/her Exchange Server. Let us know how this works.

Regards,
Seth

I forgot to mention...Local Settings is a hidden folder, so make sure you have 'View hidden files and folders' selected in Folder Options.

feldmans - if the problem follows the user to another machine, then the OST file is not the source of the problem.

Simon.

Yes.. as I stated above, I login as this user on a brand new machine and have the same issue. So as Sembee said, it can't be the .ost.

Sembee,
I can understand going for the quickest fix in some cases, but as I stated bove, the user can access their email via OWA, so they are not dead in the water.

I'm just surprised that with all the Exchange Experts around here that there aren't more suggestions. I'll give it a few more hours this morning, and if nothing more happens here I'll call Microsoft and see what the Technet support can do for me.

There is now another user that is having the same issue. I can login with his account to a new machine and it comes up with the same error.. and he works fine through OWA.
These 2 users are at different locations as well, so it's not site related.

We only have 1 exchange server, so no fancy replication issues.

Any other suggestions? Anyone?

I don't fully understand how or why... but this KB article solution fixed my problem, though the problem it is supposedly the solution for is not the problem we were having.

http://support.microsoft.com/kb/830836/en-us

Had to increase the allowed number of connections/objects on the exchange server, then restart the system attendant... voila.

Worked for me too, thanks MustangZ!!!!!

I had the exact same problem on a workstation and it turned out to be an incorrect DNS server IP

i tried the following methods and it worked:
1. move the mailbox
2. enter user ntid under user Iogon name - can be found at accounts tab
the field was missing earlier.

So what was the solution? We have thie same exact problems off & on, but gets solved by itself after few hours. Mostly this problem arises after our users experience network interuptions from remote sites and then couple of users can not connect to the Exchange server after network is back up and runing. We let the users use the OWA until the problem gets fixed by itself. We have spent hours trying to find a solution, but had no luck.

I am sure Mustangs problem aslo got solved by itself after few hours and co-incidently he tried the fix at the same time which might have made him belive that fixed the problem.

This problem occurs when a user has opened too many MAPI connections to the exchange server.

Microsoft has this to say about it: http://support.microsoft.com/kb/842022

I had the same problem and fixing it was quite easy once I figured out the cause.