Outlook 2007 is very slow

Last reviewed on May 29, 2013

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\<username>\Local Settings\Application Data\Microsoft\Outlook
Windows 7 and 8: C:\Users\<username>\AppData\Roaming\Microsoft\Outlook

Type or paste this shortcut in the address bar of Windows Explorer then press Enter to jump to the folder in either OS:

%USERPROFILE%\Local Settings\Application Data\Microsoft\Outlook

Extend.dat:
Windows XP: C:\Documents and Settings\<username>\Application Data\Microsoft\Outlook
%USERPROFILE%\Application Data\Microsoft\Outlook

Windows 7 and 8: C:\Users\<username>\AppData\Local\Microsoft\Outlook
%localappdata%\Microsoft\Outlook

Frmcache.dat:
Windows XP: C:\Documents and Settings\<username>\Application Data\Microsoft\Outlook
%USERPROFILE%\Application Data\Microsoft\Outlook

Windows 7 and 8: C:\Users\<username>\AppData\Local\Microsoft\FORMS
%localappdata%\Microsoft\Forms

Views.dat:
Windows XP: C:\Documents and Settings\<username>\Application Data\Microsoft\Outlook
%USERPROFILE%\Application Data\Microsoft\Outlook

Windows 7 and 8: C:\Users\<username>\AppData\Local\Microsoft\Outlook
%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

More Information

The update described in KB933493: Description of the update for Outlook 2007: April 13, 2007 appears to help with many performance issues in Outlook 2007.
Outlook and Slow HTML – this relates to slow typing in HTML message.
Recurring Meeting Bug – affects Dell Laptops with Media Direct
Help! My Email opens slow – for older versions of Outlook

Written by

Diane Poremsky
A Microsoft Outlook Most Valuable Professional (MVP) since 1999, Diane is the author of several books, including Outlook 2013 Absolute Beginners Book. She also created video training CDs and online training classes for Microsoft Outlook. You can find her helping people online in Outlook Forums as well as in the Microsoft Answers and TechNet forums.

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