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I have someone that wants to add hundreds of other users email accounts to Outlook. We've tried in the past and run into issues with random Outlook errors. Is there any guidance as to how many Exchange accounts Outlook can reasonably handle?

We have disabled cached exchange mode for the remote mailboxes. We have also upgraded his computer so that Windows and Outlook are both 64-bit, along with having 8GB of memory with nothing else installed.

Clearly 1-5 mailboxes work fine, but is there anything official, or any literature that I can show him that shows that it's not designed for that (or maybe that it is).

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I'm just curious why he wants to add hundred of email accounts to a single outlook. It just sounds so silly. And just a thought, wouldn't it be easier to get all the Exchange accounts to forward their mail to one account and have that account be on outlook? – Jay Dec 30 '11 at 16:25
When there are issues within the company, he wants the ability to go into anyone's account and quickly view the conversation. It will be a rare event, but he wants the instant, convenient access. You're right, it is a bit silly, but that's how he wants it unfortunately unless I can find something official that says it's a terrible idea. Ideally, I would have a Microsoft page saying it's not supported, but I don't think they specify any limits explicitly. – Jason Young Dec 30 '11 at 16:32
Oh I see, so forwarding all the mail to a single account would not really be optimal for that usage. Wouldn't it be easier to just access a specific mailbox through Exchange OWA. Rather than look through hundred of tabs in outlook for the specific user(IF you ever got it working that way), you can just go straight into a user's mailbox through OWA. – Jay Dec 30 '11 at 16:41
Why does this person want access to these accounts. Wouldn't it be easier to just forward the conversation? Hell make it company policy to bcc the person on all emails. Beyond the fact its a horrible invasiion of privacy ( I understand nothing is every private in this situation ) you obviously have attempted it int he past and failed. I am not familar with the inner workings of exchange, I am sure there is a way to setup a bcc that always happens, you would need a great deal more then 8GB of memory to load hundreds of email accounts ( which results in millions of emails ) being loaded. – Ramhound Dec 30 '11 at 16:59
As Jay points out, Outlook really isn't the correct tool to do this, using the mangement tools for Exchange likely would be a better idea. – Ramhound Dec 30 '11 at 17:00

By default, you can add up to 10 Exchange accounts in Outlook 2010. To add more accounts you will have to use registry tweaks. I think it pretty speaks for itself.

Here is the Microsoft link you asked for:

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This is using 1 exchange account, with permission to additional mailboxes. I was able to get it to work with dozens without any tweaks. – Jason Young Jan 3 '12 at 3:37
Then specify this in your question, because additional mailboxes are not email accounts. – thims Jan 3 '12 at 13:00
Really? Now are they not? You're talking about multiple exchange connections. This is one connection to get multiple mailboxes (which I believe are the same as email accounts in this case). – Jason Young Jan 4 '12 at 22:10
In terms of Outlook they are not. – thims Jan 5 '12 at 10:26
I'm with @thims on this one, Mailbox != Account – May 5 '12 at 1:43

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