Outlook Reading Panel - slow refresh?

Start outlook by typing outlook /resetnavpane

Also check the setting as in the pic below. It might be possible the outlook is downloading only the Headers and when the user tries to switch to other mail, outlook is trying to get the entire mail (causing slowness). Uncheck "on slow connections download only headers" to force outlook download entire mail and not just headers.
 In case outlook is slow ever after downloading full items, try launch outlook by typing outlook /safe in run window.
Also, check the internet connectivity (speed). Is browsing fast, or is it slow ?

The posts on the link below may also help. Especially disabling email scanning via 3rdd party anti-virus like Norton, PC-Cillin. It also says you have to remove Dell Media Direct, if present.

http://www.labnol.org/forums/topic/outlook-2007-slow-opening-messages

Dell connect was another application shipped with dell computers, even that used to slow internet connection. We used to uninstall the software and BINGO, internet speeds go crazy on clients computers.

Thx for suggestions. We don't have any Dell clients, all HPs :)

Will try the /resetnavpane next time on site.

Did what Mody suggested. Seems to having some imporvement at first but getting slower and slower again. Have not put Outlook in non-cache mode to see if any different.

Mailboxes aren't large at all, mine is only 400Mb!!

Does outlook become slow (taking 15 seconds) if users switch between mails already READ or does it ONLY happen when users switch between the UNREAD mails ? It the slowness is only when switching between UNREAD, it could be connection issue (network speed).

Is internet browsing fast ? As this is happening with the entire site, you may check stuff at the gateway. If all client computers connect to a single gateway, then the gateway can also be a point of failure.

It varies - internet browsing is OK despite issue with Outlook. I have done what Mody suggested so will give it a day or two  to see any improvement.

Only a handful of users report the problem and no problem with internet.

Looks like it is slow when switching between UNREAD emails.

However network connection seems OK and stable - internet is normal. As mentioned in my question that we are (this site) is linked to the main Office (where all the servers are inc Exchange) with a 100Mb leased line, so in theory we are getting 100Mb connection from all Production servers (internet through this leased line too). Not sure if this 100Mb is the reason but not all users at my site complaint such.

Any more suggestion?

Let that set of people use Outlook Web Access for some time and note if any delay switching between unread mails. If YES, it cannot be an issue with the client software. It has to be a network issue or some problem towards exchage. If OWA can switch FAST between mails, then it has to be an issue with the OS or the Client.

** I assume it not to be an issue with the client (Outlook) or OS (not many can behave like this at once). I would suggest you to concentrate ove network.

As I mentioned in post above yours I did suspect network issue too; while I am based in an office that is connected to the HQ (with all servers) via a 100Mb leased line I am thinking that's the reason why most people in my site are having this problem, whilst people in HQ don't.

More or less I am hoping someone to confirm that this is normal behaviour of Outlook through a 100Mb leased line so that I might convinced my boss to upgrade to a 1Gb line :)

I am not sure about the daily traffic that moves IN and OUT through the 100Mb line. I would assume 100Mb is quite sufficient (again, I can be wrong). If the bandwidth is an issue than the normal internet browsing should also be slow on the computers. Test the internet speed on the computers http://speedtest.net/ 

Are those emails huge ? I think the emails would be of few kilobytes and should not have such negative impact on a 100Mb line. (100Mbps = 125 MBps). 125MB is not that great, I would advise you to monitor the server / clients traffic. Also, make sure the clients are not using heavy bandwidth applications like (audio and video streaming, "youtube" or not downlading heavy stuff)

** You may convince your boss to get a 1Gb line and in case that doesnt fix the issue, then ?

Thx for your suggestion that was a good point at the end, if upgraded and not fixed then what?? Don't want to loss my job on that so no I won't suggest an upgrade.

I think I will defraq the info store this weekend and see how it goes.

I have defrag the priv1 database in weekend but that doesn't solve my problem. Scrolling through UNREAD emails are still slow (takes 5-8 sec sometimes ovewr 10; and it occasionally freeze Outlook for a little while too). Scrolling through READ mails are OK.

Internet browsing don't seem to be affected when such happens. I am suspecting it is the 100Mb leased line but still, nothing else is affected apart from this. Corrupted Outlook or corrupted ost?

Add into the mix people at local site (where servers are base) do have same problem as Outlook being slow (sometimes frozen) when scrolling through UNREAD mails. READ mails are fine.

So in this case we can rule out the problem is with the 100Mb leased line.

Mailboxes size shouldn't be the issue as I am only having a 200Mb mailbox.

Have tried combination of cache/download header etc as suggested but none resolves the issue. I am beginning to think it could be hardware (I/O) issue but that isn't easy to pinpoint.

Thx for your help.