Outlook stuck outbox- Not conventional 'stuck' either

Hi Guys,

We have a single user here that has problems with stuck outbox messages in outlook. Off of only one of his email accounts in his profile. Off of only his computer. There are definitely some patterns of characteristics from the emails though, which I would imagine have something to do with the problem. They are: They almost always include attachments, they've always got multiple recipients and CC's, and they're almost always replies in threads of emails being sent back and forth.

Clearing out and recreating his profile doesn't help, doing the standard "take off some of the 'RE:'s in the subject line", throw it in drafts and then re-send it, copy-and-paste it into a new message altogether... some of these randomly help solve problems at total random, but 99% of the time they don't work.

My only workaround that works completely is using a virtual box (or logging in through another PC), setting up his profile and forwarding the stuck message from the outbox on the alternate computer.

Now obviously that means it's not our email host, and it's not some strange format or character that's universally just not able to send... what happens with these messages is that they aren't even looked at, they don't even begin to send (sometimes attachments would explain a delay as it would take time to send out a big file), they're just ignored permanently on his computer.

I obviously see a solution would be to switch out his desktop, but that's kind of like saying "my hard drive's being slow, let's just reformat" before you even try cleaning it up a little. I'm assuming it's down to an application problem within Outlook or something obviously software-based. It's so intermittent though, and it works normally so often, that it doesn't seem like an Outlook re-install would do much good anyway because nothing is permanently broken, it does work sometimes. Does anyone have any idea what the root of these stuck email problems are? Is there anything I can do? Thank you

Yeah sorry about that, I should have included those details.

We're in an SBS2011+Exchange 2010 environment, the culprit email is not Exchange hosted though, it's running off an external IMAP host.

We run McAfee Enterprise v8.8, every single client runs it so the software is all uniform there.

We do have a spam filtration system, that's an awesome point. I'll go ahead and check that out, see if his account has some kind of strange rule or filter enabled.

I've definitely tried to force it in every way shape and form, of course send/receive aswell in every condition.

That is the only Outlook profile set up for him. Our system is very unique here as almost every employee has a different setup, and we have 2 legally separate but technically the same companies working in one office, so having separate hosts and separate physical servers (and eventually sites) make this situation complicated. The .pst file should have been the first thing I checked, so thanks very much for the tip there Zepher. We don't use .pst's for our exchange hosted accounts, but he's one of the few users that has the separate external IMAP account... and we only recently transitioned everyone to IMAP from POP3 less than 2 months ago (and people had massive .pst files after years of POP3 use) so an old .pst linked to his live account could definitely be a possibility.

I did check the spam filter and it's totally clean, nothing strange going on there with recipients or addresses that correspond to the outbox problem mails.

The start-from-scratch approach I'm sure will work, but rebuilding a computer completely for the single small (but very annoying) problem of the glitchy mailbox seems like overkill... but seriously this problem is making me want to punch babies at this point, so I'm not far off from having to resort to it.

Thanks very much for the tips guys, all good ideas.