Is this configured in cached mode?
The standard recommendation whether in cached mode or not is to have fewer than 5,000 items per folder otherwise performance may be impacted. So if they have multiple folders with greater than 5,000 items they need to move some messages into other folders.
If this isn't in cached mode you will want to check the disk I/O average write and read latency to see if it is within normal numbers... which should be less than 25ms.
I have the same problem --
I have about 75 people using Outlook 2002/2003 (all 2003 are in Cached mode) about 1/2-3/4 are having problems - really slow response when :
scrolling between messages (5-12 seconds for the preview pain to catch up) or even when they click on one message then jump to another and back again
I have checked several users (one only has 68 items in her inbox) total box size is 155MB Cached mode
This all started Monday 7/9/2007 Over the weekend I installed Forefront Client security and deployed it
Full scan @ 2AM, virus Scan (Realtime) and Malware on. Quick Scans every 6 hours (until things settle down)
the msMpEng.exe goes to 100% usage for about 5-12 seconds and Outlook freezes (whole PC is frozen)
No other applications seem to cause the msMpEng.exe to go crazy like this, just Outlook
Disk time is fine, just CPU @ 100% as a result of some form of conflict...
Heres how I fixed it - and it also seemed to fix general slowness. Including firefox - which is weird.
Load internet explorer options and in the advanced tab select reset internet explorer settings.
Fixed the problem for me, apparently due to some sort of restricted of trusted site settings.
Hope this helps
This works for me too, but I also found that I can then switch the security zone back to Restricted Sites and Outlook will remain snappy, at least for the duration of the current session. As soon as I quit and restart Outlook, it will go back to being slow to open/preview messages until I once again change the security zone.
I have exactly the same problem but in Outlook 2010, with Exchange 2010 SP1.
When the users selects a message in the deleted items and he then scrolls down with the arrow key and pressed Shift key, Outlook response very slow...
does anybody know a solution?