Last reviewed on May 29, 2013   —  21 Comments

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:

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

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

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

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

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


  1. amanda says

    My outlook is not responding, and typing is very slow. I have to wait for my letters to catch up before I can move my cursor. Also, I keep getting sen/receive errors. It won't open up right away either, it takes a long time, and forget downloading.

  2. kenorrha says

    I have been battling Outlook problems ever since W7 was installed on my computer. With the help on this page I have been able to fix it. Thank you!

    Btw: To begin with the mouse did not recognize Outlook at all & nobody could help me, but installing SP2 for Office fixed it.

  3. Chuck says

    solution one worked! I have been working on this for some time, now, digging, searching, trying stuff. Wish I had seen this a long time ago.

    THANKS, if I can donate, let me know!

    • Diane Poremsky says

      Changing default browsers isn't an end-all-be-all and it's better to figure out why Outlook 2007 is slow and fix it. The experience will be much better, regardless of the browser you choose.

  4. shirley says

    Nothing has worked so far for me, i have tried all of the above - still trying. I am open to suggestions.

  5. vrschrn says

    Please note: I am uing an outlook in Dutch version, so the translated names I use in the following may not be identical to the egli names.
    I experienced the same problem of outlook 2007 being slo: it was solved when I went to one of the personal folders (sent items), right click on folder sent items, select properties, go to TAB autoarchive, select buton "standard seetings for archiving, press on the next screen the button "these ajustments apply to all maps",Ok, OK. Suddenly outlokwas superfast agian

  6. Lokesh Jangir says

    I have tried all the solutions on windows 7, have removed all files. Tried with renaming the outlook folder, creating new profile, disabling all add-in and all. But still my outlook hangs when i open a mail contains a attachment. I have installed outlook fixes also. But nothing works for me.
    Please suggest me a solution.

    • Diane Poremsky says

      Yes. Not all of the .dat files are using in 2010, but other than that, the steps will works.

  7. J Fisk says

    Thank you very much. I think the problem was with the outcmd.dat file mentioned in Solution 1. I couldn't find it at first, but the problem carried on after I'd deleted the other three mentioned. Then found the outcmd.dat file and Outlook now back to normal. Brilliant

  8. Nooto says

    I have recently had some problems with Outlook 2007 running very slow when typing in an html e-mail. Loading of images was very slow and when pressing enter for a line feed it would freeze for 3 seconds. I tried all the suggested solutions but to no avail.
    After some troubleshooting I found that a non-default ICC color profile in Windows was causing the slow behaviour. After setting this back to the system default the performance was back to normal again.

    Search for Color Management in the control panel, or run colorcpl.exe
    Color Management > Advanced Tab > Device Profile > System Default

    This was on a fully patched Windows 7 system with Outlook 2007 SP3

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