An extension failed to initialize in outlook 2003. Why?

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  • Start date Start date
G

Guest

When I open Outlook now, it says "An extension failed to initialize". I
don't know what extension or why it is appearing out of no where now. How
can I repair this.
 
With Outlook closed, find and rename extend.dat to .old.

--
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.

After furious head scratching, kak asked:

| When I open Outlook now, it says "An extension failed to initialize".
| I don't know what extension or why it is appearing out of no where
| now. How can I repair this.
 
Use Windows Search (enable searching hidden files.)

--
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.

After furious head scratching, kak asked:

| Where do I find extend.dat?
|
|
| "Milly Staples [MVP - Outlook]" wrote:
|
|| With Outlook closed, find and rename extend.dat to .old.
||
|| --Â
|| Milly Staples [MVP - Outlook]
||
|| Post all replies to the group to keep the discussion intact. All
|| unsolicited mail sent to my personal account will be deleted without
|| reading.
||
|| After furious head scratching, kak asked:
||
||| When I open Outlook now, it says "An extension failed to
||| initialize". I don't know what extension or why it is appearing out
||| of no where now. How can I repair this.
 
I had the same error message and found this posting to get rid of the
problem. I found the extend.dat file in the following:

C:\Documents and Settings\Local Settings\Application Data\Microsoft\Outlook

Now Outlook is running fine. Thank you Milly Staples [MVP - Outlook]
 
Glad you got it working.

--
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.

After furious head scratching, tata asked:

| I had the same error message and found this posting to get rid of the
| problem. I found the extend.dat file in the following:
|
| C:\Documents and Settings\Local Settings\Application
| Data\Microsoft\Outlook
|
| Now Outlook is running fine. Thank you Milly Staples [MVP - Outlook]
|
|| Use Windows Search (enable searching hidden files.)
||
|| --Â
|| Milly Staples [MVP - Outlook]
||
|| Post all replies to the group to keep the discussion intact. All
|| unsolicited mail sent to my personal account will be deleted without
|| reading.
||
|| After furious head scratching, kak asked:
||
||| Where do I find extend.dat?
|||
|||
||| "Milly Staples [MVP - Outlook]" wrote:
|||
|||| With Outlook closed, find and rename extend.dat to .old.
||||
|||| --ÂÂ
|||| Milly Staples [MVP - Outlook]
||||
|||| Post all replies to the group to keep the discussion intact. All
|||| unsolicited mail sent to my personal account will be deleted
|||| without reading.
||||
|||| After furious head scratching, kak asked:
||||
||||| When I open Outlook now, it says "An extension failed to
||||| initialize". I don't know what extension or why it is appearing
||||| out of no where now. How can I repair this.
 
As said; rename extend.dat. If you can't find it use Search or use
OutlookTools (free) to locate the folder for you;
http://www.howto-outlook.com/products/outlooktools.htm

--
Robert Sparnaaij [MVP-Outlook]
Coauthor, Configuring Microsoft Outlook 2003


-----
b said:
Where do i find extend.dat

Milly Staples said:
With Outlook closed, find and rename extend.dat to .old.

--Â
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.

After furious head scratching, kak asked:

| When I open Outlook now, it says "An extension failed to initialize".
| I don't know what extension or why it is appearing out of no where
| now. How can I repair this.
Click to expand...
Click to expand...
 
Milly,

I used Windows Search (enabled searching hidden files and subfolders) but
could not find the "extend.dat" file. I'm using Office 2003 in a Windows
Vista Home Premium PC. Can you help?
 
Check the file associations related to the file named in the error.

We had a similar problem with the message "An extension failed to initialize: Can't open EXTEND.DAT." in Outlook 2003. All of the rights were correct and the user had complete access to those files. We also tried the other suggestions listed here and at other forums, including registry fixes.

Upon investigation, we noticed that the default icon for the Extend.Dat file was a CD. It occurred to us that the staff onsite at that location had recently loaded a PC tutor program. That program created a default file association with the .DAT extension.

Seeing this, the problem became clear: Outlook was using the default launch command for the program associated with the extension. In other words, Outlook called EXTEND.DAT and tried to PLAY a CD instead of OPENing a .DAT file.

To fix:

- Close Outlook.
- Open any Windows Explorer window.
- Select TOOL / FOLDER OPTIONS from the top menu.
- Click the FILE TYPES tab.
- Scroll through the list and find the .DAT extension.
- Select the .DAT extension and then click the DELETE button.
- Press OK to exit.

If your issue was the same, you should now be good to go.
 
Richard V said:
We had a similar problem with the message "An extension failed to
initialize: Can't open EXTEND.DAT." in Outlook 2003. All of the
rights were correct and the user had complete access to those files.
We also tried the other suggestions listed here and at other forums,
including registry fixes.

Upon investigation, we noticed that the default icon for the
Extend.Dat file was a CD. It occurred to us that the staff onsite at
that location had recently loaded a PC tutor program. That program
created a default file association with the .DAT extension.

Seeing this, the problem became clear: Outlook was using the default
launch command for the program associated with the extension. In
other words, Outlook called EXTEND.DAT and tried to PLAY a CD instead
of OPENing a .DAT file.
Click to expand...

Sorry, but this doesn't wash with me. Outlook doesn't care one whit what
application you might have associated with DAT files. It doesn't use the
file associations when it opens its own files. I don't doubt for a moment
that your problem was cured somehow, but it wasn't because you had a music
program associated with DAT files. I have a program that I use to open DAT
files (a binary editor) and I have DAT files associated with that program.
The DAT file icons indicate this association. Outlook doesn't care at all.
Extend.dat opens without a hitch when Outlook starts.
 
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