We're seeing many reports of Outlook 2007 being very, very slow. As of this date, we don't know the cause but we do have some possible solutions. Before trying these solutions, install the Outlook Performance update

Solution 1:

Rename or delete outcmd.dat, extend.dat, views.dat and frmcache.dat. Outlook will recreate these files as needed.

Look for these files at the following locations in Windows XP or Windows 7 & Vista:

Outcmd.dat:
WinXP: C:\Documents and Settings\%USERPROFILE%\Local Settings\Application Data\Microsoft\OutlookExtend.dat:
Windows XP: C:\Documents and Settings\%USERPROFILE%\Application Data\Microsoft\OutlookWindows 7 and 8: C:\Users\%localappdata%\Microsoft\OutlookFrmcache.dat:
Windows XP: C:\Documents and Settings\%USERPROFILE%\Application Data\Microsoft\OutlookWindows 7 and 8: C:\Users\%localappdata%\Microsoft\FormsViews.dat:
Windows XP: C:\Documents and Settings\%USERPROFILE%\Application Data\Microsoft\OutlookWindows 7 and 8: C:\Users\%localappdata%\Microsoft\Outlook

Solution 2:

Create a new PST. Although the Outlook 2007 PST is essentially identical to the PST format new to Outlook 2003,Outlook 2007 writes additional data to the PST.

If this fixes the problem, import or move your items from your old PST to the new one.

Solution 3:

Create a new profile. No need to delete the old profile just yet, just make a new one to see if the problem is fixed.

If this fixes the problem, you can delete the old profile.

Solution 4:

Disable Outlook Setup Add-in (Instant Office add-in by Cyberlink) on Dell computers that have Media Direct installed. This add-in is responsible for converting meeting requests to recurring meetings and creating calendar and contact folders when saving attachments. It also slows Outlook down.

Go to Tools, Trust Center, Addins and locate the add-in. At the bottom of the screen, select Manage: COM add-ins and click Go. Remove the checkmark from the Cyberlink add-in and close the dialog.

Solution 5:

Uninstall Business Contact Manager