Extend.dat cannot start

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Guest

When Starting Outlook 2007 in Windows Vista I am getting this error message:

An extension failed to initialize. Cannot open file extend.dat. The file
may not exist, you may not have permission to open it blah blah blah.. Can
someone help?
 
Close Outlook. Find extend.dat. Rename it to extend.old. Restart Outlook.
 
Thanks! That did it!
Jim

Russ Valentine said:
Close Outlook. Find extend.dat. Rename it to extend.old. Restart Outlook.
--
Russ Valentine
[MVP-Outlook]
Jimmymacvista said:
When Starting Outlook 2007 in Windows Vista I am getting this error
message:

An extension failed to initialize. Cannot open file extend.dat. The file
may not exist, you may not have permission to open it blah blah blah.. Can
someone help?
Click to expand...
Click to expand...
 
renaming extend.dat doesn't work for me

wallbash.gif
I'm running Vista SP1 & Office Enterprise 2007, but unusually have dedicated a partition to email (E-drive) which makes backing up both normal data and emails easier to backup. The e-drive is on the upper part of my 500GB data drive2 (with G-data partition beneath it), the C & D drives (applications and work/temp partitions) on boot drive1, both having mirrors by RAID1.

I get the tedious "An extension failed to initialize" at every Outlook startup but with nothing helpful telling me actually what extension it is, but more importantly preventing Outlook from automatically downloading email as part of the powerup/boot sequence, which is a real pain.

I've had three goes at solving this, three batches of Google searches and three sets of file/menu explorations, none of which have proved fruitful.

extend.dat is/was on the e-drive(E:\_email\Outlook-Current), but renaming it hasn't forced Outlook to regenerate it correctly. Can I get a "generic" one that will suffice?

I have looked at add-ins (via Tools/TrustCenter/Addins/manage). I only have COM add-ins, but the cause is none of the ones you can switch off. I even managed to change the outlook command startup line to switch off add-ins, but it had no effect (can't remember if I kept that one, though; currently the command is "C:\Program Files\Microsoft Office\Office12\OUTLOOK.EXE" /recycle).

The problem kicked in after installing a Microsoft keyboard and a logitech laser mouse, but did later disappear after one of the myriad Vista updates pre SP1. The full SP1 brought it back again!

Suggestions short of reinstalling Outlook appreciated (migration from W2k/Office2k to Vista/Office 2007 was a nightmare I don't want to revisit)
 
Last edited:
now I'd posted, of course I found the answer....

Well, blow me - after spending yet another session at this, I've found there WAS an extend.dat on the C-drive;

C:\Users\User\AppData\Local\Microsoft\Outlook

What the one on the e-drive was, I know not. But renaming this one (which was 0kb big) has now forced Outlook to regenerate a correct one and yes, the error has now gone.:D

Phew.

It is worth noting that the file didn't show up in a Vista Windows Explorer search for extend.dat, unless I went into the advanced search and ticked the "show system files" box - which is why I didn't think the file was on C, and that the one on E was the one to change...
 
Hi jimmymacvista. I have just bought office2007 and outlook does exactly what
yours does and I have vista premium. Is there a solution to this or have you
had any luck opening it?

best regards
David
 
I have tried this and this will not work for me. I think that I have renamed
the correct file and restarted outlook on numerous times but still the same
problem.
 
Russ Valentine [MVP-Outlook];10267062 said:
Close Outlook. Find extend.dat. Rename it to extend.old. Restart Outlook.
--
Russ Valentine
[MVP-Outlook]
"Jimmymacvista" <[email protected]> wrote in message
news:[email protected]...
> When Starting Outlook 2007 in Windows Vista I am getting this error
> message:
>
> An extension failed to initialize. Cannot open file extend.dat. The file
> may not exist, you may not have permission to open it blah blah blah.. Can
> someone help?
Click to expand...

:thumb::cheers::dance: russ valentine is like the smartest guy in the world - thanks worked..love solutions that are that easy !
 
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