Outlook 2007 LDAP very slow under Windows 7




I have been using Outlook 2007 in Vista and XP for some time now. There is a
bug that is still unresolved since Outlook 2003 (I believe) that causes LDAP
searches to take very long and hang up Outlook while doing so.

There is a registry hack that successfully circumvents this:


It has worked fine for us under all versions of Vista and XP. However I
recently upgraded to Windwos 7 Ultimate (32-bit) and it seems this workaround
no longer works. Anything that requires an LDAP lookup (such as CTRL+K in an
address field) will hang up Outlook for at least 30 seconds before it brings
up a search window or it finds the name, and then another 30 seconds or so
when moving between fields or sending the message.

For the record, the N2K file is fine and it actually autocompletes jsut
fine. It is when the name is not found in AutoComplete that this happens. If
I remove LDAP altogether and search only against the GAL or my personal
contacts, this does not happen.

For reference:


Our LDAP servers are running either OpenLDAP or Sun Enterprise Directory



Roady [MVP]

That registry key should still work on Windows 7 as well. Did you already
apply SP2 and additional hotfixes for Office 2007?




That registry key should still work on Windows 7 as well. Did you already
apply SP2 and additional hotfixes for Office 2007?

Robert, thank you for your prompt response. Indeed, I am running
12.0.6514.5000 SP2 MSO 12.0.6425.1000

I have confirmed that it is indeed Windows 7 causing the issue. I say
this because I just upgraded my workstation at home and the same thing
is happening. For further information that may help, both were
upgraded from Vista.

The workstation in the office went from Vista Enterprise x86 to
Windows 7 Ultimate x86
At home, it went from Vista Ultimate x64 to Windows 7 Ultimate x64

I have a CLEAN INSTALL on a laptop at the office that I just put
Office 2007 and will test on a clean install and see ifthis has any

The registry key for the LDAP search hack (as we call it) should
indeed work as it is not a Windows related key per se :)

If I remove the LDAP servers from my profile, address lookups are very

I can give you the LDAP config of our LDAP servers if you'd like to
try... they are public facing anyway. Thank you.

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