Outlook Consumes 100% CPU and Stuck at 99% Send/Recieve

For a long time I had a problem where my Outlook client would get stuck at 99% Send/Recieve and at the same time consume 100% (or as much as it can) CPU.

I have two different computers (XP and Vista) running Outlook 2007 against Exchange 2007 (Hosted Exchange) wich had the exact same problem.

When I looked at the Send/Recieve Details it usually said something like “Synchronizing Hierarchy” or just “Updating Inbox”. If I did Cancel Send/Recieve the CPU went down to normal.

After looking at the Synchronization Log messages in the Sync Issues folder I found a zillion messages like this:

08:46:56 Synchronizer Version 12.0.4518
08:46:56 Synchronizing Mailbox ‘Max Flodén’
08:46:56 Synchronizing Hierarchy
08:47:09 Synchronizing server changes in folder ‘Inbox’
08:47:09 Downloading from server ‘ex2.myisp.se’
08:48:02 69 item(s) added to offline folder
08:48:04 Synchronizing server changes in folder ‘Deleted Items’
08:48:04 Downloading from server ‘ex2.myisp.se’
08:48:05 Done
08:48:20 Microsoft Exchange offline address book
08:48:20 Not downloading Offline address book files. A server (URL) could not be located.
08:48:20 0X8004010F

So, the problem seemed to be with the Offline Address Book (OAB).

To make a long story short – after working back and forth with my Hosted Exchange ISP, Googling, creating and recreating Outlook profiles etc – the solution turned out to be that I needed to add a DNS entry for my domain in order for Outlook to Autodiscover which was the problem all along.

Autodiscover CNAME autodiscoverredirect.myisp.se

After adding this DNS entry for my domain it did not even take a minute before I got a dialog box asking me “Allow this website to configure [email protected] server settings?”

And that was it – no more stuck at 99% and no more Outlook consuming all CPU. Finally!

[Update: Found a Microsoft Knowledge Base article that describes this in more detail: A new feature is available that enables Outlook 2007 to use DNS Service Location (SRV) records to locate the Exchange Autodiscover service ]

Categorized as Outlook


  1. I have a similar problem but with Outlook 2003. From time to time, I see outlook surge to 100% busy and stay there for a minute or longer. System essentially freezes. Sometimes, I can see sychronizing folders. It is just not clear to me what it is synchronizing. My mail servers are hosted by Comcast and GoDaddy.

  2. Thanks a lot my friend!! Here was the only place in the web I can find the real solution. Actually, as I am away from the office, I put a mapping in the local hosts file for the autodiscovery.

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