Missing extend.dat file in Outlook 2007

25 pts.
Microsoft Outlook
Microsoft Outlook 2007
Microsoft Outlook error messages
Microsoft Windows 7
Outlook 2007 error messages
I am running Outlook 2007 under Windows 7. On starting outlook I get the error message telling me Extend.dat is missing. having looked at all the other responses to this problem I searched for the file in order to rename it - it does not exist! How can I get outlook to make the file?

Software/Hardware used:
Dell laptop studio, windows 7 pro, outlook 2007

Answer Wiki

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Open the computer icon. In the upper left corner click organize, then click folder and search options. Click the view tab. Change folder view to show hidden folders and search again.


In Windows 7, extened.dat file can find here : C:\Users\%username%\AppData\Local\Microsoft\Outlook\
NOTE: To easily locate the folders can also use OutlookTools (don’t worry, it’s free !)
U have to rename or delete the file and lets outlook to create new one !

Remember: This file contains information and settings for registered Exchange Client Extensions. When it is corrupted, it can prevent Outlook from loading correctly.
There is no need to make a backup of this file. Upon deletion it is automatically recreated from registry information.

Hope it may help u !


Discuss This Question: 5  Replies

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  • carlosdl
    What is the complete error message ? If you are able to find the file following the procedure Technochic suggested, make sure you have the appropriate permissions on the folder. If permissions are correct, renaming the file to make Outlook create a new one could help.
    85,055 pointsBadges:
  • Bobstreak
    I have already done the above - I have seareched through the drive viewing ALL files, hidden and otherwise, and have to say that the file "extend.dat" DOES NOT EXIST on my computer. Any more ideas - please!
    25 pointsBadges:
  • carlosdl
    Creating a new profile could help. Here's a guide (it's for 2003, but it might help) Create a New Outlook Profile
    85,055 pointsBadges:
  • carlosdl
    Sorry, here's one guide for 2007: Adding/Recreating a Mail Profile
    85,055 pointsBadges:
  • normandg
    I did everything said here, it work when i open outlook, i send a test message to my other account, on yahoo, i've receive 3 x the same e-mail, i've close outlook and re start it and i have the same error comming,  as before, why this happen and does anyone else this happen ?

    10 pointsBadges:

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